When the Auheimer Mark (an old cadastral unit) was partitioned in 1786, Hainstadt was given part of the Markwald (common forest).

On 1 January 1977, in the course of municipal reform in Hesse, Hainstadt was merged with the neighbouring community of Klein-Krotzenburg under the name Hainburg.

Cutzenburch had its first documentary mention in 1175 in a legal battle between the Seligenstadt Abbey and Saint Peter's Monastery in Mainz.

After Electoral Mainz's Secularization, the Oberamt of Steinheim passed in 1803 to the Landgraviate of Hesse-Darmstadt, bringing Klein-Krotzenburg with it.

On 1 January 1977, in the course of municipal reform in Hesse, Klein-Krotzenburg was merged with the neighbouring community of Hainstadt under the name Hainburg.

The municipal election held on 26 March 2006 yielded the following results: The current mayor, Bernhard Bessel (CDU), who has been in office since 1993, was reëlected on 12 September 2004 for a third term on the first vote with 64.8% of the ballots cast.