When the U.S. Light-House Board (USLHB) took over the administration of lighthouses in 1852, they divided the country into districts and assigned an army officer to act as district engineer and a naval officer to act as district inspector. These officers oversaw the lighthouses in their districts and communicated directly with the corresponding USLHB secretary in Washington. Letters to the USLHB from the district engineers and inspectors can be found in National Archives Record Group 26 Entry 24 (NC-31) and copies of letters from the USLHB to the district engineers and inspectors can be found in Entry 23 (NC-31).
The district engineer and inspector worked out of a district office which had its own staff. Here is a 1896 letter from a District Engineer W.R. Livermore, Major of Engineers, U.S. Army, describing the qualifications of the various staff members in the 1st/2nd district office based in Boston, Massachusetts.