SF Zoo offering free admission for Bay Area residents on Thursdays in September

Bititi (L), an eleven year-old giraffe, brushes against its newborn calf at the San Francisco Zoo on August 29, 2014 in San Francisco, California. (Photo by Justin Sullivan/Getty Images)

Officials with the San Francisco Zoo are launching "Good Neighbor Free Days" on Thursdays in September for residents from nine Bay Area counties in celebration of the zoo's 90th anniversary.

Each week, visitors from a certain county will get free admission.

This Thursday, Sept. 5, residents of Santa Clara and San Mateo counties can visit for free. On Sept. 12, residents of San Francisco can visit for free. On Sept. 19, admission is free for residents of Alameda and Contra Costa counties and on Sept. 26, there is no cost for admission for residents of Marin, Napa, Sonoma and Solano counties.

Visitors must bring valid identification and each adult must bring proof of where they live.

The zoo will be open one hour later each Thursday in September and a special Happy Hour for children and adults will be held from 3 p.m. to 6 p.m. on each free day.