File with a .DGN extension contains a two or three dimensional project – a drawing created with the MicroStation software developed by Bentley Systems. It can be stored in the ISFF standard (Intergraph Standard File Format) or V8 DGN (DesiGN).

MicroStation software is used to design constructions. DGN files can be also browsed with a free application – Bentley View, and also with several other programs by other producers. Utilising AutoCAD LDT, the DGN format can be transformed into more universal DWG format, supported by most programs.