During the eighteenth century, the Posts maintained by the Dutch were at strategic positions so as to control respectively the upper Essequibo, the upper as well as the lower Cuyuni, and the coast district, which together included the whole area claimed by the Dutch.

The Dutch, since the middle of the eighteenth century, assumed the right to control trade in the upper regions of the Essequibo as well as the Mazaruni and Cuyuni. In addition, the British in 1810 made a treaty with the Carib chief, Manarwan, who lived in the upper Essequibo, whereby the Amerindians agreed to submit themselves to British jurisdiction.

It was equally clear that the Dutch were recognised as having similar rights in the Mazaruni District. Spanish Amerindians, coming from the Spanish Missions, asked for the permission of the Dutch Commanders to settle in that locality. In 1748, when the Spaniards began to attack and kidnap Amerindians in the area near the head-waters of the Cuyuni River, the Spanish Commander was warned by the Dutch Commander of Essequibo, Laurens Storm van Gravesande, of the consequences which might ensue from such conduct. Gravesande, on this occasion, decided to give permission to the Amerindians to make reprisals. When it was reported in 1767 that Spaniards had incited the Akawois against the Caribs in that district, Gravesande forbade the Caribs to injure that tribe, on the ground that they were Dutch subjects.

In 1833, Amerindians who had migrated from Venezuela settled at a point ten days' journey up the Cuyuni River where they regarded themselves as in British territory, since the "Spanish frontier" at that time was considered as situated at the head of the Mazaruni and Cuyuni Rivers. The districts of Amakura and Barima were occupied by Amerindians who also acknowledged the protectorate and jurisdiction of the Dutch.

The Caribs were the most important tribe of these regions, and trade was carried on between them and the Dutch. In 1684 a party of Caribs, who had been expelled from Suriname by the Governor, settled in Barima. They allied with the French with whom they acted against both the Dutch and the Spaniards in the war which was fought at that time. But this was only temporary, for the Essequibo Dutch made friends with these Caribs by the end of the century. The Barima District was from then considered as within the sphere of the Postholder of the Pomeroon.

British jurisdiction, after 1802, was exercised in the district of the Barima River and its western tributaries, the Aruka and the Kaituma. The Amerindians were unanimous in affirming in 1839 to Crichton, Superintendent of Rivers and Creeks, that the Spanish, and later the Venezuelan, authorities never exercised jurisdiction east of the Amakura.

In 1849, Mc Clintock, the Postholder of the Pomeroon, formally appointed Amerindian captains for upper and lower Barima, Barama and Waini. This succession of captains was never interrupted in the nineteenth century.

The magistrate of Pomeroon, Everard Im Thurn, who was appointed in 1882, supervised the district as far as Amakura, and from 1886 exercised jurisdiction up to the banks of that river. In 1891 he was appointed Government Agent for the North-West District, then carved out of what had previously been the Pomeroon District. He took up his residence at Morawhanna, at the junction of the Mora Passage and the Barima, and administered the area as far as Amakura. Under his administration, police stations were established at Amakura, Barima Point, Morawhanna and at Koriabo on the upper Barima.