For a longer time Civ 3 modders thought, that 362x362 is the maximum map size for Civ 3 maps. El Mencey created such a map a long time ago. In this post Quintillus showed, that the tile limit for Civ 3 is 65,535 tiles and posted about a 420 x 312 map:
https://forums.civfanatics.com/threads/earth-420-x-312-wip.652386/
Even the old TeTurkan map was 256x256.
My mods CCM1 and CCM2 hold a random map size of 250x250. Earlier versions of CCM1 had much bigger map sizes, but to have fun on such big maps needs frequently a lot of additional settings. Per example, there must be enough cities to fill such a big map (the NCL patch is not working well), the trade system should be cut down to avoid 'monster' turn times, the speed of ships and the range of aircraft must be adjusted, otherwise your sailing ships will face battleships when they arrive at their destination, only to name some of the problems of big maps.
Please play CCM2 and you will see, that 159x159 is not the limit for a C3C map size.