Birth control pills that are expired or no longer needed should be disposed of according to FDA guidelines. Ideally, medications should be dropped off at safe drug disposal sites. Most Walgreens and other pharmacies have a safe medication disposal kiosk. You can find a disposal location near you, as well as more information on safe disposal here: https://nabp.pharmacy/initiatives/awarxe/drug-disposal-locator/
If you can’t get to a safe disposal site, you can dispose of your pills in the regular trash. It’s best to mix them with an unpalatable substance such as used coffee grounds, cat litter, or dirt, then seal the mixture in an airtight bag and dispose the sealed bag in the garbage. This reduces the chances that a child or animal would accidentally ingest the medication, or that the hormones would leach into our groundwater.
Never flush pills down the toilet, as the hormones can leach into our groundwater supply.