"KILMALCOLM. The town stands 7 miles east-south-east of Greenock; sprang from an ancient church dedicated to King Malcolm III; was till recently a curious sequestered place; and now has a post office, with money order department, under Paisley, a railway station, a banking office, a spacious hydropathic establishment of 1880, Established, Free and United Presbyterian churches, and a large public school. Pop. 1170."
[From The Gazetteer of Scotland, by Rev. John Wilson, 1882.]
Various gazetteers differ as to the origin of this placename. For a period in the 18th century, Kilmacolm was generally spelled 'Kilmalcolm', based on a presumption that the settlement's name was derived from Malcolm III, one of the former kings of Scotland. In 1905 the accepted spelling became 'Kilmacolm', the general consensus now is that Kilmacolm takes its name from the Gaelic language meaning a cell or church of Columba, derived from the dedication of its ancient church to St. Columba of Iona.
You can see maps centred on OS grid reference NS360696 (Lat/Lon: 55.891566, -4.624105), Kilmalcolm which are provided by: