Lichau Creek is an 8.9-mile-long (14.3 km)[3] southwest-flowing stream in Sonoma County, California, United States, which flows through the town of Penngrove and discharges into the Petaluma River.

O'Hara was born in 1833 in County Sligo, Ireland and settled in Penngrove sometime between 1852 and 1857 and died in 1911 at the age of 78 years.

Descending initially to the west, it crosses under Sonoma Mountain Road and passes north of Stony Butte.

It immediately bends southward and parallels the tracks through Penngrove, crossing Adobe Road and Main Street.

On the northern outskirts of Petaluma, it crosses Ely Road and turns southwestward, crossing Old Redwood Highway, the North McDowell Boulevard Extension, U.S. 101, and Stony Point Road to reach the Petaluma River.