Also to answer the question in a little more detail, there are several ways of finding locations I highly recommend using together to get the clearest picture possible of what's available to explore around you. There's already some good tips in this thread, but I'll elaborate on what I use. I travel a lot, so I like to do a bunch of research before I enter a region to maximize my odds of success.
-City GIS Maps: Most medium sized towns and up will have GIS maps of major utilities like storm drains that list, among other details, pipe diameter. Whether these maps are available to the public varies from city to city, but if you can access them they'll be useful for mapping out storm drains and finding accessible manholes to large diameter systems.
-US Geological Survey maps: The USGS has maps available to the general public online that list every single mining resource in the country. While they usually contain plenty of useful information, the real gem are the coordinates for mine adits (horizontal access tunnels). These coordinates will usually get you within a 30 meter radius of the adit, which is usually enough to find it with a little bit of poking around. That being said, these maps don't discriminate between active and abandoned mine features, so while it's an excellent resource you should do more research online about any prospective mine you think you might hit.
(NOTE: This one will be very useful to you in Nevada. That being said, RESEARCH THE PRODUCTS OF THE MINE BEFORE ENTERING. Many of the mines in the Southwest are either uranium or coal, which are FAR more dangerous than normal mines- and normal mines are dangerous enough. I personally wouldn't recommend running mines until you're a lot more experienced. Surface structures such as mine headframes, ore mills, tipples, and tumblers should all be fine though.) -Social Media: I tend to lurk "Abandoned [CITY/STATE/REGION]" Facebook pages. It's 95% crap, but once in a blue moon someone will post something that makes periodically checking these pages worth it. Googling "urbex in [area] reddit" and checking location-tagged posts on Instagram and Youtube can sometimes help too, though this is of varying usefulness.
- Wikipedia: A quick Google search will unearth pages devoted to listing decommissioned military installations, power plants, and ghost towns in most states, complete with full names and sometimes even exact coordinates. I cannot understate how useful this is, and I've had moderate success using data scrapping tools to quickly compile these pages into maps- though doing it manually will work just as well, even if it is slower. This one will be useful to you, given the number of ghost towns in Nevada. Just be aware that even if Wikipedia lists a place as a ghost town with a population of zero doesn't mean that there won't be some cranky old off-the-grid folks lingering in a ghost town.
-City redevelopment proposals: The wheels of bureaucracy usually move slowly and always leave behind a trail of paperwork a mile long. If your city has any urban renewal/demolition/redevelopment plans in the works regarding vacant/derelict buildings, rest assured there will be proposals, contract bids, and committee meeting minutes galore for months or even years ahead of time.
-Declassified military information: Shuttered airbases, munition depots, radar stations, missile silos, and weapons testing facilities dot the country, and most are public information. Given that the White Sands Missile Range in New Mexico had sub installations across the southwest during the Cold War, these might yield something in your area. The website
Bombs In Your Backyard is also useful, especially for determining which hazards you might encounter at a military site. It's good to know if you should watch out for unexploded ordinance before you get there, after all.
-Google Maps: Saving the best for last, this is the gold standard. I use it to verify that whatever I've found from other sources is likely still standing, and to plan my approach long before I ever arrive. You can also scour riverbanks and shorelines for outfalls, trawl college/hospital campuses for steam tunnel hatches, or follow railroad tracks in search of buildings that look derelict from orbit. I've had some good success with both. It shouldn't be the only tool in your arsenal, but Google Maps is a massive force multiplier for your research ability.
-Google Lens: This one is changing the urbex game, especially with posting exterior shots. Even if someone posts something online without tagging the location, all it takes is for one other person to name drop it in their post and Google Lens will find it. Still kind of hit or miss, but it's undeniably powerful- much to the consternation of many, many explorers. Just because its existence bothers us doesn't mean we can't use it now that the genie is out of the bottle, though.