Nampa containers go to the Pickles Butte Sanitary Landfill at 15500 Missouri Avenue, Nampa, Idaho 83686. It is Canyon County's own facility, run by the County's solid waste operation under a county Solid Waste Director, and the County's advisory committee meets at the landfill office itself. The site takes calls on 208-466-7288.
Published hours are Monday through Saturday from 8 am to 5:30 pm, and the County states that gates close at 5:30 pm rather than staying open for the last truck in the queue. Being inside the city limits, it is a short run from almost anywhere in Nampa, which is why a full container here can often be swapped the same day rather than the next.
The holiday position is published in unusual detail and it is genuinely useful. The landfill is closed on New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day, and it is open on December 26th and January 2nd. It is also open on Idaho Human Rights Day, Presidents' Day, Columbus Day, Veterans Day and Juneteenth, which catches a lot of people out in the other direction.
The County publishes a landfill fee schedule separately, and no rate was readable on the department page, so no figure is quoted here. Your account manager settles the destination and the rate for your load before the unit leaves the yard.
One last operational point that matters for a construction load. The County is bound by federal rules on asbestos cover, which is why the 3 pm cut-off exists and why the manifest is checked at the weigh-in. If your job involves any asbestos, it is a conversation to have at the quote stage.