The exploration for, and recovery of, sub-sea hydrocarbons has a history of about sixty years. The craddle of the international offshore oil and gas industry was the Gulf of Mexico, but within a few decades the industry spanned the globe. The international offshore oil and gas industry was introduced in the North Sea in the 1960s, and this paper outlines the way that oil and gas from the North Sea has developed into a major economic and social force for Denmark and especially for Esbjerg, the base harbour for offshore activities in the Danish portion of the North Sea. The aim of the essay is to underline the fact that the offshore oil and gas industry is as maritime as any - and the paper offers a methodology for isolating the regional/local impact of the industry from overall national effects. It examines the knock-on effect of offshore activities for the Esbjerg area as reflected in businesses, jobs and turnover. The development of the region's offshore activity is reviewed and the proportion of the Danish offshore market covered by companies in the Esbjerg area is examined. In an international perspective, the Danish offshore sector and its centre of gravity in the Esbjerg area are among the smallest pieces in the jigsaw puzzle. But the little pieces are the most numerous and are therefore indispensable to the history of the international offshore sector.