The brig Maria of Mönsterås, also called "Åström's Maria". Between the years 1898 and 1908 Maria belonged to Mönsterås. During that period she was the largest ship in Mönsterås. She had two owners. In 1909 she was sold to Helsingör in Denmark.

The crest, was confirmed by the Government in 1955 as the crest of Mönsterås borough. After the fusion of the municipalities of Fliseryd, Mönsterås and Ålem 1st January 1974 it became the crest of the new municipality.

The Banner with the name Mönsterås, the Brig Maria and the crest all together create the complete trademark.