Skip to main content
Official websites use .gov
A .gov website belongs to an official government organization in the
United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Monitoring location Mercer Lake, West Basin Deep Hole, at Mercer, WI - USGS-460945090040600
Important for you to know:
- USGS will be performing maintenance on WDFN webpages beginning Tuesday, May 12. If you cannot access the page you are intending or are unexpectedly redirected to a different page, please reach out to wdfn@usgs.gov for assistance.