Zeeland is the westernmost and least populous province of the Netherlands. The province, located in the southwest of the country, borders North Brabant to the east, South Holland to the north, as well as the country of Belgium to the south and west. It consists of a number of islands and peninsulas and a strip bordering the Flemish provinces of East and West Flanders. Its capital is Middelburg with a population of 48,544 as of November 2019, although the largest municipality in Zeeland is Terneuzen. Zeeland has two seaports: Vlissingen and Terneuzen. Its area is 2,933 square kilometres (1,132 sq mi), of which 1,154 square kilometres (446 sq mi) is water; it had a population of about 391,000 as of January 2023.

South Holland is a province of the Netherlands with a population of over 3.8 million as of January 2023 and a population density of about 1,410/km2 (3,700/sq mi), making it the country's most populous province and one of the world's most densely populated areas. Situated on the North Sea in the west of the Netherlands, South Holland covers an area of 3,308 km2 (1,277 sq mi), of which 609 km2 (235 sq mi) is water. It borders North Holland to the north, Utrecht and Gelderland to the east, and North Brabant and Zeeland to the south. The provincial capital is the Dutch seat of government The Hague, while its largest city is Rotterdam. The Rhine-Meuse-Scheldt delta drains through South Holland into the North Sea. Europe's busiest seaport, the Port of Rotterdam, is located in South Holland.