The main lock was constructed from 1952 to 1957 and is 1,200 feet (366 m) long and 110 feet (34 m) wide with a lift of just over 38 feet (12 m) and large enough to handle a full-length tow of barges.
It was put into operation in 1957 at a cost of 13.5 million dollars.
The 1957 lock replaced a 1910-1913 lock.
The 1913 lock was a variant of the standardized Panama Canal design and was 110 feet (34 m) wide, 358 feet (109 m) long and 57 feet (17 m) tall with a 40 feet (12 m) lift.
There was a 130 feet (40 m) wide, 463 feet (141 m) long and 20 feet (6 m) deep dry dock at the site, both the dry dock and 1913 lock were dewatered in 1977 when a sheet pile and cell closure were built blocking the upstream sides of the lock and dry dock.

The lock and dam, as well as the rest of the river, can be viewed from a distance on the Observation Deck of the Keokuk Rail Bridge.
The main lock was constructed from 1952 to 1957 and is 1,200 feet (366 m) long and 110 feet (34 m) wide with a lift of just over 38 feet (12 m) and large enough to handle a full-length tow of barges. It was put into operation in 1957 at a cost of 13.5 million dollars. The 1957 lock replaced a 1910-1913 lock. The 1913 lock was a variant of the standardized Panama Canal design and was 110 feet (34 m) wide, 358 feet (109 m) long and 57 feet (17 m) tall with a 40 feet (12 m) lift. There was a 130 feet (40 m) wide, 463 feet (141 m) long and 20 feet (6 m) deep dry dock at the site, both the dry dock and 1913 lock were dewatered in 1977 when a sheet pile and cell closure were built blocking the upstream sides of the lock and dry dock.
The lock and dam, as well as the rest of the river, can be viewed from a distance on the Observation Deck of the Keokuk Rail Bridge.
Lock and Dam No. 19