Sinclair Mills was a flouring mill which burned in 1859.

• Fire in Ann Arbor Village-- Sinclair's large Flouring Mill Nearly Destroyed. - Ann Arbor Local News, November 22, 1859; via GSWC

On Sunday morning last about 7 o'clock our citizens were alarmed with the cry of fire. It was soon ascertained that the large flouring mill situated on the north side of the Huron, in the Village of Ann Arbor, belonging to William M. Sinclair, was on fire. The fire department of the village and of our city were promptly on the spot, but the flames had already so far advanced that all hope of saving more than the lower story was abandoned.