O'Sullivan was a native Alexandrian (?) and an expert draftsman and surveyor. He was born May 14th, 1855, and lived in New York from 1871 until 1881, when he secured a job with the U.S. Coast and Geodetic Survey in Washington DC. In 1881, when fire destroyed the north side of the 700 block of Alexandria's Gibbon Street, O'Sullivan drew the plans for two replacement houses. He died of consumption in March 1886.
This collection is comprised almost entirely of correspondence relating to O'Sullivan's work with the U.S. Coast and Geodetic Survey during the late 19th century.