Montserrat, a British Crown Colony, has been mapped by the Directorate of Overseas Surveys (now Ordnance Survey International (OSI)) and the principal map is a single sheet at 1:25,000 scale (DOS 359). This was first published in 1963 and was compiled photogrammetrically from air photography flown in the 1950s. The subsequent editions incorporated revisions from large-scale mapping and local information. They have also been redesigned in a tourist style and printed in process colors. The projection is Transverse Mercator, Clarke 1880 ellipsoid (modified). The relief is shown by 50 ft contours supplemented by hill shading and layer tints. Edition 5 (1978) has a UTM grid, while the latest edition 6 (1983) has the BWI grid and an additional arbitrary alphanumeric labelling of the squares for local referencing.
Large scale contoured mapping was first undertaken in the 1970s initially covering Plymouth and the west at 1:2,500 scale and the eastern part of the island at 1:5,000. Currently, 38 sheets at 1:2,500 (DOS 059) are available in varying editions, revised to 1989, and cover much of the island. The remainder of the island is covered by seven sheets at 1:5,000 scale (DOS 159), also revised to 1989.
Soviet military topographic mapping of Montserrat exists at the following scales: 1:1,000,000 (1 sheet, complete coverage, published in 1966); 1:500,000 (1 sheet, complete coverage, published in 1986) and 1:200,000 (3 sheets, complete coverage, published in 1966-1967). These products are available in print, digital raster and digital vector GIS formats from East View Geospatial.