Where is most of Earth's fresh water actually kept?

Most of Earth's fresh water is actually frozen in huge ice sheets and glaciers near the North and South Poles, locked up as solid ice rather than flowing in rivers or sitting in lakes. These massive ice masses hold far more fresh water than every river and lake on the planet combined.

Deep underground caves and clouds over deserts do hold small amounts of water in certain places, but neither comes close to matching the enormous volume of fresh water frozen solid in the world's ice sheets and glaciers.

If all that frozen ice were ever to melt, scientists estimate it would raise sea levels around the entire world by many meters, which is part of why melting polar ice is watched so closely.