Lichau Creek is an 8.9-mile-long (14.3 km) southwest-flowing stream in Sonoma County, California, United States which flows through the town of Penngrove and discharges into the Petaluma River. The original name of the creek is O'Hara Creek and is named after the settler, John O'Hara, who purchased and owned the land through which the creek flows. 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. The October 26th, 1904 Santa Rosa Republican refers to this creek as O'Hara Creek.