Retsof is in northwestern Livingston County, in the southeastern part of the town of York.

According to the U.S. Census Bureau, the Retsof CDP has an area of 0.5 square miles (1.2 km2), all land.

In March 1994, the ceiling in one of the large underground chambers collapsed, the first of a series of effects caused by groundwater entering the salt deposit, which had been dry for all of the 110 previous years of mining at the site.

The effect of filling all this space lowered the aquifer, leaving many drinking water wells dry, and led to surface subsidence, even sinkholes 200 feet (61 m) wide, damaging structures and highways.

[4] The U.S. Geological Survey studied the effects of the mine collapse on groundwater hydrology in the surrounding watershed.