By Friesland and the Lauwers Zee, N.
The rivers of Groningen descending from the Drente plateau meet at the capital, whence they are continued by the Reitdiep to the Lauwers Zee (being discharged through a lock), and by the Ems canal (1876) to Delfzyl.
GRONINGEN, a town of Holland, capital of the province of the same name, at the confluence of the two canalized rivers the Drentsche Aa and the Hunse (which are continued to the Lauwers Zee as the Reit Diep), 16 m.
Besides the Reit Diep, there are the Ems Canal and the Damster Diep, connecting it with Delfzyl and the Dollart, the Kolonel's Diep with Leeuwarden, the Nord Willem's Canal with Assen and the south and the Stads-Canal south-east with the Ems. Hence steamers ply in all directions, and there is a regular service to Emden and the island of Borkum via Delfzyl, and via the Lauwers Zee to the island of Schiermonnikoog.
The city was again walled in 1255; before 1284 it had become a member of the Hanseatic league; and by the end of the 14th century it was practically a powerful independent republic, which exercised an effective control over the Frisian Ommelande between the Ems and the Lauwers Zee.
In 1439 it decreed that no one might trade in all the district between the Ems and the Lauwers Zee except burghers, and those who had purchased the burwal (right of residence in the city) and the freedom of the gilds.
The Zuider Zee and the bay in the Frisian coast known as the Lauwers Zee also gradually came into existence in the 13th century.
Groningen communicates with the Lauwers Zee by the Reitdiep (1873-1876), while the canal to Winschoten and the Stadskanaal, or State canal (1877-1880), bring it into connexion with the flourishing fen colonies in the east of the province and in Drente.
In Friesland, finally, besides the ship canal from Harlingen to the Lauwers Zee there are canals from Leeuwarden to the Lemmer, whence there is a busy traffic with Amsterdam; and the Caspar Robles or Kolonels Diep, and the Hoendiep connect it with Groningen.