Quote Originally Posted by Papewaio
In MTW if you have an inn and minimal law type structures (castles) then you get more Mercs, IMDHO if you buy more, more will be attracted to that province... mind you it has been ages since I played MTW.
Indeed. M:TW Mercenaries like undeveloped provinces (that is, no advanced castles or governement buildings) near warzones, and where mercenaries have been hired before.

In the unit files, certain units are marked as "possible mercenaries", and I think these will be generated as mercs near the places where they can be recruited. Also your disbanded units will enter the merc pool. Also, merc units seem to move about, never staying long at the same inn.

R:TW mercs are less mobile. R:TW provinces are grouped into regions and each region has it's own mercenary pool. A mercenary pool is allocated certain units and these units will generate there until a maximum has been reached (generation speed and maximum are different for each unit and region). There is nothing you can do to influence this.