Development of the Mississippi and the most westerly regions of British holdings in Louisiana depended upon there being easy access from other parts of  the colony and other British colonies further afield.  With New Orleans still under Spanish control, despite British rights to use the river freely, it was not a comfortable situation as access to the river through the delta was controlled by Spanish pilots.  The only other access to the Mississippi region was either from the North via river access from Pennsylvania or overland through Indian territory from the Carolinas and Georgia.  All were perilous and as early as 1770 George Gauld had advocated that the British establish rights to their own route through the mouth of the river.

There was however a further option open to the British, if they were able to establish the fact of the geography.  The Treaty of Paris in 1763 had ceded the river Iberville to the British. If the British could accurately establish that the river did indeed link Lake Maurepas with the Mississippi, and that it was navigable then potential threat from New Orleans and the lower reaches of the Mississippi would be negated.  With the river Iberville to the north and the Mississippi to the south New Orleans was effectively an 'Island'.  The unfortunate reality proved to be that the Iberville and the Mississippi rivers only met when the latter was in full flood as the Iberville was as much as 12' higher at the 'junction' on Manchac.  Further, the Mississippi was so frequently congested with trees and debris washed down river at such times of flood that it was perilous to navigation.  The chart presented here details in large scale insets the British plan to overcome these obstacles with the construction of a canal, a plan with Gauld himself clearly supported.

Virtually all of the settlements marked on this magnificent plan of the river Mississippi are long ago forgotten in name but were the foundations for a number of current day towns and cities which now thrive on the old river.  Most notable of all of the developments is of course New Orleans itself which is quite charmingly, and accurately, depicted as a small gridded town.  Further north up the river Mississippi the now defunct British settlement of Manchac along with the ruins of Fort Bute are depicted at the intersection of the Iberville and Mississippi rivers.  Manachac was just South of the now State Capital, Baton Rouge.  Above the town of Natches the origins of modern day Vicksburg may be seen at the junction of the Mississippi and the 'Lusachitta’ or Black River.  Of note are the family names (and number) of British estate and plantation owners who had already established claims down the east bank of the Mississippi between Vickers and Baton Rouge.  Gauld himself purchased one thousand acres on Thompson Creek next to his friend Dr Lorimer in 1772, and later in 1773 a further thousand acres nearby.  Clearly, there was a great deal of optimism amongst the business and political class that this region was a good investment.

In the making of the overall plan, Gauld certainly pushed the boundaries of his brief to survey the British territories.  As Gauld himself stated 'For although we had no right or authority to survey beyond the Mississippi, yet a general knowledge of that Coast is absolutely necessary for vessels bound to the River..' The fact that he extended the survey as far as what even in those days was Texas is simply explained as 'on purpose to make the Plan Square'  This of course is typical Gauld. Both artistic in his lay-out, informed and politically astute.  By laying out the plan as he does, Gauld marked the Mississippi the very center of the map - not as an extremity.  He further steals the moment to provide a view of the entire most northerly part of the coastline of the Gulf.  Again, in a style now familiar, Gauld includes handwritten notes and commentaries across the plan.  His comment on the coast westward of the Mississippi states that 'This coast does not run so far to the Northward as it has been laid down in several draughts, particularly that published by Mr Jeffreys in his West India Atlas 1775'.  This is of course a reference to Thomas Jeffreys, Geographer to the King and renown London map publisher.  It illustrates perfectly Gauld's knowledge of contemporary material.

Just to keep a perspective on the humanity which went along with life in these regions at the time it is well worth noting Gauld's mark of a 'Wreck' at the mouth of the, now, Sabine River or what was then, the Chicowansh River.  On his original draught for this Plan Gauld made the following note to explain the entry:

‘The Wreck at the Entrance of Chicouansh was a sloop from Jamaica bound for the Mississippi. Having fallen into the west they bewildered themselves on this inhospitable coast and after they were cast away, the Savages plundered them and the vessel of everything they could carry off, even the sails and rigging.  Only three people remained out of the nine, the Master and all of the rest having died on the coast.  These three men in a small boat wandered along the coast for some months in quest of the Mississippi, but after a fruitless search they had returned to the Wreck for some provisions, and were just going away again, when providentially the Surveying sloop Florida appeared and relieved them from their distress July 27th 1777, after they had been eight Months from Jamaica.’

Finally, as a point of interest it worth noting that Gauld, on his 'unofficial' tour westward was accompanied by Mr John Payne with whom he had struck-up a professional relationship whilst making a Plan of the Harbours of Port Royal and Kingston Jamaica in 1772.  Gauld and Payne has worked closely thereafter, until Payne's death as a result of an engagement with an American Privateer 'Morris' which was commanded by an ex British merchant skipper called William Pickles, now working for the Spanish on the 29th August 1779.  It was the first engagement of the long anticipated war between Britain and Spain over the British territories.