Col. William H. Sinclair (October 31, 1838-January 11, 1897) was an American Union Army officer, Freedmen's Bureau official, businessman, state legislator, and union officer.

Sinclair founded the Beach Hotel in Galveston in 1882, in an effort to increase tourism in the city.

[2] He also served as president of the Galveston City Railroad Company.

On January 17, 1897 he was buried at Lakeview Cemetery in Galveston.

This article about an American businessperson born in the 1830s is a stub.