Products include:
Forgotten Realms Adventure hardcover (2e) - includes full city map, and city description in the "Forgotten Realms Adventures"-style (go figure!) - still considered the best format of city descriptions.
Volo's Guide to the Sword Coast (2e) - a very good book that greatly expands on Baldur's Gate. Includes a city map and many more locations (including, for example, a full description of the Elfsong Tavern).
There is mention of Baldur's Gate in a smattering of other products, but those two above have the most detailed information out of all the FR products.