Most of the low-elevation lakes are the remnants of long glacial valleys dammed at their outlets by end moraines. Look at a map of the park and you will see these finger-like lakes stretching away from the Continental Divide. Just like the U-shaped valleys they often fill, these long lakes have a bathtub shape—deep with steep sides. At 10 miles long (16 km) and 464 feet deep (141.4 m) Lake McDonald is both largest and deepest body of water in the park.