The former post office building is located in the center of Canandaigua, on the west side of North Main between Atwater Place and Greig Terrace, on the corner with the former.

Canandaigua's city hall, also a contributing property to the historic district, is opposite the park on the south, across West Street.

Across North Main, a four-line road with a narrow planted median strip at this point,[3] is the Ontario County courthouse, also a contributing property.

[2] Behind the post office is a parking lot, beyond which the railroad tracks curve,[3] following the contour of the terrain, which gently slopes southward toward the north end of Canandaigua Lake.

At the top of the entire portico is an anthemion set between the engraved words "A.D. MCMXI" and capped with volutes on the end.

On either side are pedestals with pedimented pylons supporting cast iron anthemia-shaped lamps with glass globes.

A secondary entrance near the east corner has two paneled wooden doors with a crosetted upper light and blind transom.

To its west, two barred windows open into the basement as the driveway rises toward the former loading dock at the end of the block.

The water table continues, supported by brackets at the base of the two largest first-story windows, set with narrow four-light casement in the same surrounds as their counterparts on the east.

[2] The second story on the south side has one-over-one double-hung sash with no surrounds, likewise set deeper than the east windows.

A brown brick extension with some architecturally sympathetic elements continues further west; it was built by the YMCA after the Postal Service discontinued use of the building and is not part of the NRHP listing.

At the top of the pilasters is a plaster Doric entablature and crossbeams with a Greek key design similar to that seen on the east facade.

[2] By the later decades of the 19th century its location at the north end of Canandaigua Lake made the city a popular destination for summer residents.

[2] The Thompsons became very committed to Canandaigua, funding the planting of trees along its streets and founding the hospital building later used as county offices.

But the Tarsney Act of 1893 allowed a limited number of commissions, such as the 1900 Ellis Island Immigrant Inspection Center, to be awarded to private architects.

[2] Allen produced a building less restrained than his other ventures into the Classical Revival mode, which often used simple engaged pilasters on their front facades rather than the full colonnaded portico he employed in Canandaigua.

[6] A third story was built on the roof inside the parapet, and a small two-bay extension was added to the west (rear) elevation.