Andrew Onderdonk, American surveyor and contractor (d. 1905)
Andrew Onderdonk (30 August 1848 – 21 June 1905) was an American construction contractor who worked on several major projects in the West, including the San Francisco seawall in California and the Canadian Pacific Railway in British Columbia. He was born on August 30, 1848 in New York City to an established ethnic Dutch family. He received his education at the Rensselaer Polytechnic Institute.

He married Sarah Delia Hilman of Plainfield, New Jersey. After starting his career surveying town sites and roads in New Jersey, he headed west to work as a general manager for financier Darius Ogden Mills on several engineering contracts. He died in Oscawana-on-the Hudson, New York on June 21, 1905.