First historical note dates back to 1102 and it mentions the area because of its rich salt deposits. Much of Berchtesgaden's wealth has been derived from its salt mines.
During the Napoleonic wars, Berchtesgaden changed hands a few times. Salzburg was always interested in Berchtesgaden and French troops occupied the area a short time. Berchtesgaden came under Bavarian rule in 1810 and became instantly popular with the Bavarian royal family, which often visited Königssee and maintained a royal hunting residence in the town itself.
Nascent tourism started to evolve and a number of artists came to the area, which reportedly gave rise to "Malereck" (literally painter's corner) on the shore of Königssee. The most famous author who lived in Berchtesgaden was Ludwig Ganghofer.
The area of Obersalzberg was appropriated by the Nazis for their senior leaders to enjoy in the 1920s. Hitler's mountain residence, the Berghof, was located here.
-Partly from Wikipedia