Anza-Borrego Desert State Park.

• Size: 650,000 acres — the largest state park in California, larger than Yosemite National Park.
• Counties: San Diego, Imperial, and Riverside.
• Designation: International Dark Sky Park (since 2018).
• Visitors: ~600,000/year — about a fifth of Joshua Tree's traffic on a park twice the size.
• Gateway town: Borrego Springs, completely surrounded by the park.

1. Borrego Palm Canyon (3 mi RT, easy). Sandy wash into a hidden palm grove fed by a year-round spring.
2. The Slot (2 mi RT, moderate). A narrow mudstone passage you walk through, shoulder-width in places.
3. The Wind Caves (1 mi RT, easy scramble). Sandstone caves overlooking the Carrizo Badlands. Sunset is unreal.
4. Mountain Palm Springs (2.5 mi loop, easy). Six separate palm groves in the south end of the park.
5. Calcite Mine (4 mi RT, hard). Steep scramble to a WWII-era mining site. Crystals everywhere.

In strong rainfall years (typically following an El Niño winter), Anza-Borrego erupts in gold, magenta, and lavender for two to three weeks in late February through early April. Even an average year is worth a March visit. Follow the Anza-Borrego Foundation wildflower hotline before booking — timing shifts by 2–3 weeks annually.

The park has two developed campgrounds (Borrego Palm Canyon and Tamarisk Grove) and primitive open camping is allowed almost everywhere. For everyone else, the town of Borrego Springs has hotels, resorts, and vacation rentals — including Moonlight Oasis, a 3-bedroom dark-sky house with a pool, hot tub, and rooftop telescope deck.

• Entrance fee: $10/vehicle at developed sites; the rest of the park is free.
• Cell signal: zero a few miles outside town. Download maps offline.
• Best season: October through April. May–September daytime highs exceed 105°F.
• Visitor center: 200 Palm Canyon Drive, Borrego Springs. Free park maps and wildflower updates.