Bridge District Overview - Baldur's Gate 2
The Bridge District is one of the many different districts that make up the town of Athkatla. If you're playing on the Enhanced Edition this is also where you'll meet Neera for the first time in BG2. Visiting the Five Flagons Inn will also put you on the quest that leads to recruitment of Haer'Dalis, another potential companion.
Upon entering the Bridge District for the first time you'll be stopped by Lieutenant Aegisfield who will tell you about a string of recent murders that have been happening in the area. This will lead to one of the better quests of this area known as Solve the "Skinner" murders in the Bridge District.
Lieutenant Aegisfield: Your first time entering the Bridge District you'll be stopped by this man and warned about the recent string of murders. Talking to Lieutenant Aegisfield will begin the Solve the "Skinner" murders in the Bridge District side quest.
Neera: Neera is a potential companion in both BG1 and BG2 that was added into the game with the Enhanced Editions. The first time you meet here in BG2 will be at this exact location in the Docks District, she'll have a run in with some Red Wizards after which she'll teleport away. Running into Neera here is a required flag needed to encounter her later.
Horn: Inside this building you can find the Silver Horn of Valhalla item which can be upgraded by Maheer in Waukeen's Promenade into something better.
Five Flagons Inn: On the main floor you'll find Samuel Thunderburp who is an innkeep that will offer you typical innkeep services. In the basement of this building you'll find Raelis Shai and the Sigil Troupe that she is the head of; Raelis will have a couple of quests for you to complete starting with Free Haer'Dalis from Imprisonment by Mekrath. Once this quest is complete she'll offer you the follow up, Rescue Raelis and Haer'Dalis from the Planar Prison. This quest is the only way to access the Planar Prison zone which contains many good items; once you've begun this quest a portal will open in the basement that gives you access to this zone.
Tanner: Rejiek Hidesman is the name of the tanner who runs this shop and he is the man you're looking for during the Solve the "Skinner" murders in the Bridge District side quest. On the 2nd floor of Rejiek's shop you will find a bed that you can click on which will reveal Human Flesh, a piece of armor that can only be worn by Evil characters. This item can be upgraded by Fael in Umar Hills check my Finish the Leather Armor begun by Rejiek Hidesman quest entry for more info. On the final floor you'll find Gesen Bow Shaft which can also be used to make something at Cromwell's Blacksmith in the Docks District.
Bel & Rose: Both of these NPCs are involved in the Solve the "Skinner" murders in the Bridge District quest that takes place here. Bel is also a basic merchant with some equipment for sale.
Saerk Farrahd Estate: During Anomen's Companion Quest you will have to visit this building.
Delosar's Inn: Inside this building you'll find Captain Dennis who is part of the Limited Wish side quest.
Lich: This building will have a basement where you'll find a sarcophagus with a Lich enemy inside of it. Defeating this Lich will earn you the Golden Torso as well which is involved in the Restore Kangaxx's Body side quest. I'd recommend waiting until after you've completed the Underdark during Chapter 5 to defeat this enemy.
Twisted Rune: In order to access this area you will need a Rogue Stone in your inventory. You'll be teleported to a new map where a very difficult battle will take place; one of the BiS items Staff of the Magi can be found in this area. Check out my Twisted Rune Hideout Overview guide for more information.
Am-Si: Am-Si is part of the Find the Kidnappers Who Buried Tirdir side quest, he's the man in red that Tirdir sends you after. He will not spawn until you've progressed far enough into the aforementioned quest.