IRT East Side (Borough Hall)  opened 1/9/1908 This station serves the 4 and rush hour 5 trains, it is a mix of renovation and restoration to its original 1908 appearance.  However 2 of the grand "BH" mosaics on the N/B side are missing.  Platform clearly extends to the south side where you can get a close up of 2 and 3 trains turning off before entering their side of this complex, the drab 60's tile was used for the extension (if the platform extension took place today, they would use authentic replicas of Borough Hall tablets and mosaics instead.  F/T side is at the center and leads to Brooklyn Municipal Building and both sides on Joralemon Street.  The subway entrances are also preserved, however, the P/T side at east side of Joralemon and Court Streets, is renovated and has no signs of the original 1908 design.  The passageway to all other train services is at the south end.  For the first months of the 1908 opening, this was the temporary terminal until the line was extended to Atlantic Ave in May, 1908.  The N/B platform is ADA accessible from the passageway, however the S/B platform is not because no elevators were built for the IRT 4/5 platforms (despite there is plenty of space on the platform and mezzanines to build 2 elevators, one from each platform to the restored F/T mezzanine.

IRT West Side (Borough Hall) opened 4/15/1919:  This area serves the IRT 2/3 lines and has 2 tracks along 2 side platforms in a dual-level format.  The upper level serves the Manhattan bound trains and passageway to the IRT East Side station, while the lower level is for southbound (towards Flatbush and New Lots Avenues).  This area is not renovated, but is ADA accessible be means of a 3-stop elevator that covers both levels with the mezzanine level to Cadman Plaza West.  There are 2 staircases from lower to upper level, one is near the Lexington Ave passageway, and the other is near the other staircase and up escalator to mezzanine level.  Mosaic has rendition of the Brooklyn Borough Hall clock tower, across the street from the Municipal Building.  The platform extensions are clearly to the north end of this station.

The mezzanine level above the IRT West Side platforms, has 1 large street stair and elevator in from of the Brooklyn Supreme Court Building and Brooklyn Borough Hall, plus 2 newer staircases on the S/W of Cadman Plaza and Montague Streets.  Because of the installation of the ADA elevator at this area, it was converted from P/T to full time status, the original hours at this booth were from 6:15 AM to midnight daily. Alongside where the elevator inside fare control, the mosaic band is the imitation to the original band along the same mezzanine.  The shape of the subway entrances, the tiles, and the font of the signs, all clearly show these exits were constructed in the early 1960's. The elevator entrance at street level, recreates the 1900's look ad is similar to the elevator outside Brooklyn Bridge-City Hall IRT station.   After passing through fare control there is a passageway to the BMT portion of this complex.  As we walk down towards the escalator,  there is a sealed entrance to a bank, with ghost booth and exit, blue tiles exist in this area and was probably a new construction in the 1960's. 

BMT Montague Street (Court Street-Borough Hall) opened 3/11/1920:  2 tracks on island platform, it has 2 staircases to mid-level, and then the escalators mentioned above.  The mosaic on the track wall shows the Brooklyn Borough Hall tower. A second P/T entrance to Clinton and Montague Streets has 1 staircase from platform to mid-level, where you can board any one of the 3 elevators to mezzanine level.  The doors open on one side at the bottom level, but open on both sides on the mezzanine level.  There are two street stairs, one of which blends in with a church upstairs.  The platform extension is to the north at the Clinton St side with a break in the platform walls, they are tunnel shaped.