The Watt Library — formally the Watt Monument Library — is one of Greenock's finest buildings and one of the oldest working libraries in Britain. Opened in 1837, it was built with money raised partly through donations from James Watt's descendants and serves as a monument to Watt as much as a functioning library. The reading room is open to visitors and is worth stepping into for the architecture alone: a soaring Victorian interior with an iron gallery and good natural light.
The library holds local history collections of considerable depth, including records relating to emigration from the Clyde — tens of thousands of people left from Greenock for the Americas and Australia during the 19th century, and the records here are among the best sources for tracing them. It sits on a street with several other notable Victorian buildings, making it part of a worthwhile short walking tour of the town centre.