California
Alameda, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Humboldt, Kings, Lake, Los Angeles, Madera, Marin, Mariposa, Mendocino, Merced, Mono, Monterey, Napa, Orange, Placer, Riverside, Sacramento, San Benito, San Bernardino, San Diego, San Francisco, San Joaquin, San Luis Obispo, San Mateo, Santa Barbara, Santa Clara, Santa Cruz, Solano, Sonoma, Stanislaus, Sutter, Tehama, Tulare, Ventura, Yolo, and Yuba counties
10/16/23 is the filing deadline for both your federal and state returns.