1842 – "Mahon's Ditch, erected in 1831, at a cost of $9,950; rebuilt by Winslow Lewis in 1839; cost unknown."
The cost of this light-house was not $9,950, but $4,975. It was necessarily placed in a wet salt marsh, frequently overflowed, and at length the foundation was so much injured, by the water acting on it, that it was found necessary to remove it to a place of safety; and this was done by Mr. W. Lewis, for $2,500. The original building and the removal of it, it will be perceived, cost $7,475, whilst the original appropriation for erecting the building was $10,000.
1850 - Mahon’s Ditch light-house. - 10 lamps; Susan Haney, keeper; supplied May 22, 1850.
This light-house, which is also the dwelling, is in somewhat of a dilapidated state, for there has not been anything done to it, except rough-made water-gutters, since I supplied it last year; then it was rather leaky about the lantern and windows, and the plastering was off in every room. It answers, I supposed, a very good purpose for the present occupant, for very little care of attention was paid to any part of the premises, except a little to the lantern apparatus. Lighting apparatus is in good burning order.
Left May 9, 1849 427 gallons. Found on hand 84 gallons. 343 gallons consumed in 378 days is equal to 331 gallons per year, or 33 1/15 gallons per lamp. Delivered 232 gallons spring oil, 100 gallons winter oil, on hand 84 gallons, for a total of 416. 73 tube-glasses, 4 gross wicks; 25 yards cloth; 1 buff skin; 1 box tripoli; 1 box soap; 1 pair scissors; 1 file.
Common burners, 14-inch reflectors; spare lamps, in good order; put on iron burners 3 burners, complete; 1 ninety-gallon oil-butt; 1 lantern and lamp; 1 butt-stand.
1855 – Since July 1,1854, lenses have been introduced into this district, as follows: At Mahon's, a fifth-order of 180°, in place of ten lamps.
1855 – At Bombay Hook and Christiana, new iron lanterns for fourth-order apparatus, and at Cohanzey and Mahon's river new iron lanterns for fifth-order, have been substituted for the old and defective style hitherto in use. These were furnished with very wide vertical astragals and inferior glasses, 9 inches by 12. The new ones have diagonal astragals, and superior French plate glass of very large dimensions. In placing these lanterns the towers have been necessarily remodelled, and in great part renewed.
1859 – The light-houses in this district are nearly all in good condition. That at Mahon's river has been condemned, and preparatory steps have been taken to rebuild it. It is deemed safe, however, for the coming winter.
1860 – A site has been selected for a new light-house at Assateague, Virginia, and a new site has been purchased for the light-house at Mahon's river.
1862 – In the fourth district, embracing the coasts from Squam inlet, New Jersey, to Metomkin inlet, Virginia, including Delaware bay and tributaries, the lighthouse service has been maintained in an efficient condition, with but slight expense for repairs and renovations, the most important work being the rebuilding, on a proper site, of the light-house at Mahon's river, which change had been rendered necessary by reason of defective original location, and subsequent encroachment of the water, imperiling the structure. These dangers have been entirely removed by the new position.
1867 – Mahon's river.—The plank platform around the building has been thoroughly repaired, and the lantern and building have been painted inside and outside.
1868 – Mahon's river.—The brick water cistern, which leaked, has been repaired, and new lantern covers have been supplied at this station.
1869 – Mahon’s River,-Del.—No repairs made and none needed at present. Small repairs may be required to be made next year.
1870 – Mahon's River, Delaware, Delaware Bay.—The abrasion of the marsh along the front of the building has been considerable. The building is on the back end of the light-house lot, and the location will have to be changed in a short time. This will require a new lot to be purchased for the building, which can probably be moved without much difficulty or expense.
1871 – Mahon's-River, Delaware, Delaware Bay.—The abrasion of the marsh at this station has been so great as to compel a change in the site of the Light house. There is a good location about a quarter of a mile north of the present site, which will serve equally well the purposes of navigation. The estimate for a screw-pile building is -$15.000.
1872 – Mahon's River, Delaware Bay.—As was stated in the last annual report, the abrasion of the marsh in which this light-house stands is so great as to compel a change of site. There is a good location about a quarter of a mile north of the present site, which will serve equally well the purposes of navigation. If all the material can be prepared ready to commence the work of erection of the structure at the site by the 1st of July next, the whole can be completed ready for lighting by the following November. If a site and right of way can be purchased, at a moderate cost, the amount asked for by the board, viz, $15,000, will be sufficient to erect a building.
1873 – Mahon's River Light Station.—In October last repairs were made to the plank platform around the building. Sketches have been forwarded showing the abrasion of the marsh at this site. For several years the board has recommended the removal of the lighthouse to a more favorable site, and as the time cannot be distant when this must be done, it is not deemed necessary to make further repairs. The amount required for the new lighthouse, as given in previous reports, is $15,000, and the time required for its erection would be about six months.
1874 – Mahon's River light station.—The monthly measurements of marsh show that the abrasion is less rapid than formerly, though still going on. The building will probably stand during the coming winter. A special appropriation of $15,000 was made during the last session of Congress for a new structure on a more secure site. A design for the new structure has been prepared, and the work will be taken in hand without unnecessary delay.
1875 – Mahon's River, Delaware Bay, Delaware.—The site of this station having been almost entirely washed away, a new one was purchased, and the erection of a new structure was commenced under the appropriation made by act approved June 23,1874. Work is now progressing satisfactorily, and the structure will be completed before the end of the season. The new site, while quite as good for the purpose of navigation, is much more accessible, and comparatively free from the action of the water.
1876 – Light shifted to new structure 1,980 feet from old one. October 20, 1875.
1876 – Mahon's River, Delaware Bay, Delaware.—The new structure at this station was completed, and the light changed from the old to the new building, on the 20th of October last. The old structure has been sold at public auction, and the proceeds turned into the Treasury. The grounds around the dwelling have been graded and raised, adding greatly to the comfort of the keeper.
1879 – Mahon’s River, entrance to Mahon' s River, Delaware Bay, Delaware. —The repairs made necessary, on account of the damage caused by the storm of October 23, 1878, have been completed.
1880 – Mahon’s River, entrance to Mahon’s River, Delaware Bay, Delaware.—The front porch was repaired, where damaged by the storm of October, 1878, and new sash-cords were put in where required.
1884 – Mahon's River, at mouth of Mahon's River, Delaware.—A number of mud holes in the marsh around the dwelling were filled up, and 2,000 bushels of shells were placed around the dwelling.
1888 – Mahon's River, Delaware Bay, Delaware.—Changed from fifth to fourth order, and a red sector of about 14 degrees was inserted to mark the Elbow of the Ledge and the Buoy of the Middle, April 21, 1888.
1888 – Mahon’s River, at mouth of Mahon’s River, Delaware Bay, Delaware.—The characteristics of this light were changed in April last from a fifth to a fourth order and by the establishment of a red sector to mark the Buoy of the Middle and the Elbow of the Ledge.
1889 – Mahon's River, Delaware.—The site of this station was filled in and graded with oyster shells.
1891 – Mahon River, Delaware Bay, Delaware.—The front of the site was protected by a pile and sheathing revetment, with returns of 30 feet on each side, backed by stone resting on brush mattresses. The roadway was resurfaced with oyster shells, two communicating doors were placed in the dwelling, and the stable was rebuilt.
1892 – Mahon River, mouth of the river, Delaware Bay, Delaware.—The site under and around the house for about 25 feet beyond the building line was filled in with marsh mud to a height, of about 4 feet. The top surface was protected with a covering of oyster shells about 6 inches deep. Cut offs were placed in the cistern conductors.
1894 – Mahon River, at mouth of Mahon River, Delaware Bay, Delaware.—The constant washing away of the bank has made it necessary to remove and rebuild the light-house structure four times since its first erection in 1831. The present station is now threatened with early destruction. The surrounding marsh is soft, yielding mud, and the building protected by its bulkhead being but 60 feet from high-water mark on the south and 125 feet on the east, the cost of further protection would be great and of uncertain results. This station is hardly of sufficient importance to justify the expense of the construction of an isolated site for its use. The present building is of wood, the outer walls being lined with brick laid in mortar; hence it would be unwise to attempt its removal over the soft marsh. The Board therefore recommends that a new site be purchased about 1,500 feet NNW. of the present site; also that a detached skeleton wooden tower, specially designed so that it could be moved if necessary, be built for the display of this light upon the proposed new site. It is estimated that this can be done at an expense not exceeding $8,500, and it is recommended that an appropriation of this amount be made therefor.
1895 – Mahon River, Delaware Bay, Delaware.—The following recommendation, made in the Board's last annual report, is renewed:
The constant washing away of the bank has made it necessary to remove and rebuild the light-house structure four times since its first erection in 1831. The present station is now threatened with early destruction. The surrounding marsh is soft, yielding mud, and the building protected by its bulkhead being but 60 feet from high-water mark on the south and 125 feet on the east, the cost of further protection would be great and of uncertain results. This station is hardly of sufficient importance to justify the expense of the construction of an isolated site for its use. The present building is of wood, the outer walls being lined with brick laid in mortar; hence it would be unwise to attempt its removal over the soft marsh. The Board therefore recommends that a new site be purchased about 1,500 feet NNW. of the present site; also that a detached skeleton wooden tower, specially designed so that it could be moved if necessary, be built for the display of this light upon the proposed new site. It is estimated that this can be done at an expense not exceeding $8,500, and it is recommended that an appropriation of this amount be made therefor.
Toward the close of the fiscal year a red sector, marking the locality of the Joe Flogger Shoal (upper end) buoy and the northern entrance to Blake Channel, was placed in the lantern of this light.
1896 – Mahon River, Delaware Bay, Delaware.—By the act approved June 11, 1896, the sum of $8,500 was appropriated for establishing this station on a new site. The proper measures for beginning this work will be taken at an early day.
1897 – Mahon River, Delaware Bay, Delaware.—The barn was raised about 4 feet to place it above storm tides. The road approach was raised somewhat and shelled. The oil was moved into a rough detached shed to wait until a fireproof structure can be provided. Minor repairs were made. A preliminary survey was made, and steps are being taken toward the acquisition of a sufficient light-house site. While the shore at the old station is still wearing, the rate is so slow that the present structure will last for a few more years.
1898 – Mahon River, Delaware Bay, Delaware.—The shore line continued to retreat during the year, and were it not for the protection afforded by the sea wall, would now lie underneath the light-house. A new reservation was selected and surveyed and a deed for it obtained. Designs for the new light house, etc., were nearly completed.
1899 – Mahon River, Delaware Bay, Delaware.—The shore line continued to retreat during the year, but not sufficiently fast to make it necessary to begin the erection of the new light-house, which work was consequently postponed. The deed to the new reservation was finally approved, and duly recorded. Various repairs were made.
1900 – Mahon River, Delaware Bay, Delaware.—Plans and specifications were made and one bid received for the building of a lighthouse, oil house, barn, and wharf. The bid, being in excess of the appropriation, was rejected. The plans will be modified and then bids will again be asked. Various minor repairs were made.
1901 – Mahon River, Delaware Bay, Delaware.—An appropriation of $4,000 was made in the deficiency appropriation act approved March 3, 1901, in addition to the amount appropriated in the sundry civil appropriation act approved June 11, 1896, for establishing this station on a new site, and bids for doing the work were called for by readvertisement. Minor repairs were made to the light-house and to the shell road leading across the marsh to the station.
1902 – Mahon River, Delaware Bay, Delaware.—Contract was made for erecting the new light-house, oil house, barn, and wharf, and foundation piles for these structures were driven. The iron foundation columns of the barn and oil house had been put in place; also ten of the foundation columns of the walk. The foundation columns of the light-house and some other material for this structure had been delivered. A topographical survey of the new reservation was made and stone-boundary monuments were set at the southeast, southwest, and northwest corners.
1903 -516. Mahon River, Delaware Bay, Delaware.—The new light-house was finished, the roof sheathed, the floors laid, the exterior painted, and interior woodwork put in place and finished. The keeper moved in and the lens was set up in the new lantern. The light was exhibited from the new light-house on June 25, 1903, for the first time.
A new barn was erected. The iron oil house was erected. The remainder of the iron foundation columns of the new walks were put in place, the deck and railing put on, and the new wharf completed. Good water was obtained by boring. Various repairs were made.
A contract was made for the construction of a road running across the marsh from the highway to the new light-station.
1904 – Mahon River, Delaware Bay, Delaware.—The contractor for building the road to run from the light-station across the marsh to the highway began the delivery of the materials. A red sector was established, cutting the buoys at the entrance channels of Murderkill and St. Jones creeks. The iron lantern on the abandoned lighthouse was taken down, its parts properly marked, boxed, and stored at the Edgmoor light-house depot. The old light-station was sold at public auction. The highest bidder, however, decided to forfeit his advance payment and not take title to the property. A second public sale is to take place on July 9, 1904.
1905 – Mahon River, Delaware Bay, Delaware.—The contractor for the construction of the road across the marsh having failed to do the work properly his contract was annulled, when the work was again advertised and a new contract made. About three-fourths of the road has been built.
1906 – Mahon River, Delaware Bay, Delaware.—The building of a road across the marsh was completed in February. This road is about 1,700 feet long and consists of a complete layer of foundation poles laid on the marsh and covered with about 8 inches of oyster shells. The abandoned light-house was, on February 3, 1906, sold at public auction.
1921 – boardwalk rebuilt, new boat davits installed, and general repairs to wharf, $1,406.
1955 – Automated light atop Mahon River Lighthouse moved to a nearby skeletal tower, and Mahon River Lighthouse was turned over to the Air Force.
1979 – Delaware Technical and Community College places Mahon River Lighthouse on National Register of Historic Places.
1982 – GSA sells Mahon River Lighthouse to Delaware Storage and Pipeline Company for $9,100.
1984 – Fire destroyed Mahon River Lighthouse on December 29, 1984.
Keepers: Abel Harris (at least 1833), John Smith (at least 1835 – 1845), Thomas E. Harvey (1845 – 1848), Susan Harvey (1848 – 1855), Thomas J. Catts (1855 – 1861), T. S. Buckmaster (1861 – 1866), William Parker (1866 – 1868), James A. Parker (1868 – 1869), William S. Vane (1869 – 1873), Henry D. Joseph (1873 – 1885), Theodore H. Burton (1885 – 1911), C. F. Burton (1911), Lewis A. Connelly (1911 – 1912), Irvin S. Lynch (1912 – 1939).