The historic old town and its Fachwerkhäuser date back to the Late Middle Ages when Ladenburg was the capital of the Prince-Bishopric of Worms.

Ladenburg lies on the Neckar alluvial cone at an altitude of 96 to 106 metres in the Rhine-Neckar Metropolitan Region in the Upper Rhine Plain.

The nearest major cities are each about eleven kilometres away, Heidelberg in the southeast and Mannheim in the northwest, with which there is no direct border.

The nearest climate station in Heidelberg measured an average temperature of 11.1 °C and a precipitation of 745 mm per year between 1971 and 2000.

The garrison included an auxilian cavalry division of the Germanic Cananefates, their name means "leek masters".

In the year 260 or shortly before, apparently Alamanni destroyed the city after the imperial troops had abandoned the decumate land.

Emperor Valentinian I retook the settlement in 369 and had a country castle, a late antique harbour fortification, built, which could only be entered from the Neckar.

Around the middle of the 5th century, probably in 454 after the collapse of the Hun Empire, the Roman rule in the Ladenburg area finally came to an end.

In Carolingian times, Ladenburg was one of the few towns in the empire that were designated as Civitas Publica, which presupposes the continued existence of the royal court.

The later reformer Reuchlin was in charge of the book collection, which was taken over from the Lorsch Abbey and supplemented with Dalberg's holdings and is known today as Bibliotheca Palatina.

On Christmas Eve in 1564, a brawl broke out between the Reformed priest Eckard and Bishop Bettendorf in St. Gallus.

Thereupon, Frederick III, the Calvinist Elector of the Palatinate had the church of St. Gallus plundered on Good Friday and Catholic images destroyed (Kurpfälzer Bildersturm).

In 1705 the brothers Elector Johann Wilhelm and Bishop Franz Ludwig von Pfalz-Neuburg agreed on a larger exchange of territory.

After the French Revolution Ladenburg was occupied in the coalition wars of 1799 and Napoléon Bonaparte rearranged the political map of Europe.

The revolutionaries succeeded in conquering the town occupied by the Prussians, thus covering the return march of the main forces.

During the Weimar Republic, they were temporarily eclipsed by the Zentrum due to the fragmentation of the left-wing party spectrum.

The Lobdengau-Museum is located in the Bischofshof (with open-air museum) and has the core themes: archaeology, town history and folk culture.

The historic factory, where automobiles were built at the beginning of the 20th century, was renovated with the support of DaimlerChrysler AG and provides a great setting for the motor history exhibits (including over 80 vehicles and other objects) of the collector Winfried A. Seidel.

The municipal elections in 2019 led to the following result (in brackets: difference to 2014):[7] The blazon of the coat of arms reads: In shield diagonally divided by silver and blue, a red castle with open gate and raised silver portcullis in the tin-plated and roofed low central part, between the two pointed outer pewter towers two diagonally crossed blue keys (beards turned up).