Where did Gulliver say the kingdom of Brobdingnag was located?

He didn't specifically say, and did not know exactly, having been blown off course. He does describe the vicinity he believes it to be, which would have placed it in the heart of Micronesia. The map that is printed with the 1726 Gulliver's Travelsindicates the northwest coast of North America, keeping in mind of course that Swift did not draw the map.