Holtville Hot Springs is a developed geothermal soaking area inside the Hot Springs Long Term Visitor Area (LTVA), about 300 acres of desert scrub on both sides of Interstate 8 managed by the Bureau of Land Management's El Centro Field Office. It sits in the low desert of the Imperial Valley, below sea level, roughly 7 miles east of Holtville and 15 miles east of El Centro. Older names for the spot include Highline Hot Well and Old Fogey Hot Springs. Hot water from an artesian well fills a set of concrete tubs inside a fenced enclosure, and the overflow runs out to a shallow pond ringed by fan palms and cattails.

From I-8, take Exit 131 (CA-115/Van Der Linden Road), turn left, then make an immediate right onto Evan Hewes Highway heading east. The pool area is about a mile along, on the right just past the bridge, directly beside the freeway. The road is paved the whole way and any car or RV can make it. There is a dirt parking lot next to the fence, plus a vault toilet. BLM's listing quotes 3.8 miles on Evan Hewes for the LTVA as a whole, but the tubs sit at its west end by the bridge.

The main tub is concrete and about 5 feet deep, deep enough to reach the shoulders of most adults. Water leaves the well at roughly 120 F and usually sits around 105 to 110 F in the big tub. Its overflow feeds a smaller, shallow tub that runs cooler, and a stock tank has been added on the same plumbing, with its temperature depending on how recently it was filled. An outdoor shower runs off the same line, and soakers are expected to rinse before getting in. There are no lifeguards. Campground volunteers drain and pressure-wash the tubs once a week (Tuesday mornings, according to visitor accounts), so the water may be low or empty then.

Day use of the pools is free. BLM charges only for camping in the LTVA: from September 15 to April 15 a permit costs $180 for the season, $80 for four weeks or $40 for two weeks, and from April 16 to September 14 you can camp free for up to 14 days. Permits are sold by the on-site hosts, at Pilot Knob LTVA about 35 miles east on I-8, on Recreation.gov, or at the El Centro Field Office (1661 South 4th Street, open Monday to Friday, 8 a.m. to 4:30 p.m.). The posted pool area curfew runs from midnight to 5 a.m.

BLM's rules sign at the gate bans food, drinks, pets and soap inside the post and cable fence, and violators can be cited. Swimsuits are required. The big tub is hot enough to cause overheating on a long soak, and summer air temperatures here regularly pass 110 F, so the season that makes sense runs from late fall through early spring. There is no drinking water, electricity or dump station on site; Holtville has water and a dump station. Traffic noise from I-8 is constant, and in winter the tubs are shared with a steady stream of LTVA campers.

The LTVA itself is the other draw. Snowbirds park RVs and truck campers for weeks or months on open desert north and south of the freeway, and sandy tracks through the tamarisk make easy walking and biking. The palm pond below the tubs draws birds, and ducks turn up some winters. A geothermal power plant nearby hums at night, a reminder of the heat under this part of the valley.