The Upper St. Regis Post Office is a seasonal post office on the St. Regis Carry Road that serves the camps of the St. Regis Lakes.

From Anson Phelps Stokes' Stokes Records, Vol. III, p. 63

"We spent the summer and autumn at Birch Island and at Shadow Brook. After I left Birch Island the St. Regis Yacht Club was organized, and I was elected commodore. As all the principal camp owners were members of the club, all matters affecting the common interests and welfare of the campers have been discussed at these meetings. These discussions led to the establishment of the Upper St. Regis post-office, to regulations preventing the pollution of the lake by sewage, dish-water, laundry water, etc.