Saxony-Anhalt Harz district (HZ number plates) Lower Saxony Goslar district (GS number plates) Göttingen district (GÖ number plates) together with the B 243 in the direction of Herzberg together with the B 243 in the direction of Barbis alternate route Hesse Werra-Meißner district (ESW number plates) under A 38 Hersfeld-Rotenburg district (HEF number plates) Fulda district (FD number plates) under A 7 E45 Bavaria Bad Kissingen district (KG number plates) Main-Spessart district (MSP number plates) Würzburg district (WÜ number plates) Würzburg city (WÜ number plates) Würzburg district (WÜ number plates) replaced by A 3 A 81 E41 E43 Baden-Württemberg Main-Tauber district (TBB number plates) Neckar-Odenwald district (MOS number plates) together with the B 292 in the direction of Neckarelz together with the B 292 in the direction of Elztal Heilbronn district (HN number plates) Heilbronn city (HN number plates) Heilbronn district (HN number plates) Ludwigsburg district (LB number plates) Stuttgart (S number plates) together with the B 10 through Stuttgart together with the B 10 through Stuttgart Esslingen district (ES number plates) Reutlingen district (RT number plates) Tübingen district (TÜ number plates) This section will not be used after completion of construction: Zollernalb district (BL number plates) together with the B 463 in the direction of Balingen-Süd together with the B 463 in the direction of Bisingen Rottweil district (RW number plates) local diversion around Rottweil together with the B 14 local diversion around Rottweil together with the B 14 Schwarzwald-Baar district (VS number plates) together with the B 33 in the direction of Hüfingen together with the B 33 in the direction of Villingen Schaffhausen, Switzerland 4 A4 Baden-Württemberg Waldshut district (WT number plates) continues to Zürich as 4 Bundesstraße 27 or B27 is a German federal road.

It connects Blankenburg am Harz with Rafz in Switzerland.

The Bundesstraße 27 crosses the following states and towns (north to south): The B27 is interrupted in two places: between Würzburg and Tauberbischofsheim, where it has been replaced by the motorways A3 and A81, and between Randen and Jestetten, where it crosses through Switzerland.

The part south of Stuttgart follows the Schweizer Straße (Suisse road), a chaussee from 18th century.