Low Lantern. An aging merchant ship now permanently docked in Baldur's Gate's harbor and converted into a tavern and gambling house. The green lantern on the bow signals the ship is open for business.
Map Notes. There are 4 levels to the ship - labelled in reverse order as you descent deeper into the ship (L1 is the top deck, L4 is the guest quarters). As usual, I've omitted corpses (of seagulls) from the map image, but have included a couple images you can place as tokens if you are running the encounter as written with the imps. Otherwise the tavern should appear as written and laid out in the source book. I added some foliage to the stairs and along the edge of the ship to really hammer home that this ship isn't going anywhere anytime soon and has been berthed for a while.
There are variants available for fog/no fog (as the preamble describes it being obscured by fog until 100ft out) and day/night variants.

Files. The zip files below are organized in 4 folders: Roll20Free for smaller 70px images; Roll20Paid for larger 140px images; FoundryVTT for 100px dd2vtt files compatible with multiple VTTs; and Printable which are 140px gridded images in color and black and white.
Low Lantern – Descent into Avernus is unofficial Fan Content permitted under the Fan Content Policy. Not approved/endorsed by Wizards. Portions of the materials used are property of Wizards of the Coast. ©Wizards of the Coast LLC.