Hobart Bay is a census-designated place that was located in Hoonah-Angoon Census Area, Alaska during the 2010 United States Census, but is now part of Petersburg Borough.

The bay was named in 1889 by Lieutenant Commander Mansfield of the United States Navy.

Hobart Bay first appeared on the 1990 U.S. Census as a census-designated place (CDP).

There were seventeen housing units at an average density of 0.1 per square mile (0.039/km2).

In the CDP the population was spread out, with two from twenty-five to forty-four and one from forty-five to sixty-four.