Know Before You Go
White Sands Missile Range is a military base, and has increased their already stringent ID requirements, so be sure to check the website to find current information, and bring a second form of ID if you're in doubt (your passport is usually the best choice). Follow instructions referring to authorized and unauthorized areas of the site. While only open to "atomic tourists" certain days out of the year, there is a historic marker on US 380, located near the Stallion Gate turnoff. The five-mile drive to the gate is still scenic, and you can see observatories up on the hills as you approach the gate. Since it's a military base, the whole area is a no drone zone.
To visit the Trinity Site on days when it is open to the public: From Socorro, head south on I-25 to US Rte. 380. Take US 380 east for 12 miles to the turnoff for the Stallion Gate. The gate is 5 miles from the highway, and you'll pass through a checkpoint here. The Trinity Site is 17 miles further—just follow the car in front of you (all other routes will be blocked and likely guarded by the military). The road is paved the entire way, and there's a very large parking area just outside the Trinity Site (pay close attention to where you parked—it's easy to get lost here). COME EARLY. Even better, be in line by 6:30 or 7 a.m. for when the gates open at 8 a.m.
From Alamogordo, the military will escort a caravan of civilian vehicles through a gate on the southeastern side of the missile range and to the Trinity Site. Exact details for the caravan are posted on the website, but it usually departs Alamogordo before 8 AM, and leaves the Trinity site to return to Alamogordo after 2 PM. However, civilian vehicles that are not in the caravan are not permitted to enter or exit using that route, so if you miss the departure, or wish to leave the Trinity Site before or after the caravan does, you must use the Stallion Gate which is a 110-mile drive from Alamogordo.