ENA poorly recognised issue in research on the military affairs of the Polish-Lithuanian Commonwealth is the question of the deployment of troops forming the Crown and Lithuanian armies during peacetime. The source material available to contemporary researchers allows an attempt to establish the number of garrisons and their distribution throughout the state only for the period after 1717. The rules for the deployment and maintenance of military detachments, introduced by resolutions of the so call ‘Silent Sejm’, meant that there were probably more than 200 permanent military locations in the Polish-Lithuanian Commonwealth. In the case of most of the military units (regiments, companies, squadron i.e) the accommodation allocated to them in 1717 did not change for 60 years (until the military reforms of the 1770s), and there were not uncommon cases, that even until the 1790s, i.e. until the end of the Crown and Lithuanian armies. But did the existence of such permanent accommodation mean that a military garrison was established? Certainly, the basic condition set out in the definitions of the term garrison, which was ‘the permanent or temporary stationing of troops’, was met. Much worse was the organisational side of garrisons - with the establishment of a proper military infrastructure (guardhouse, detention centre, lazarette, barracks and others). The same was true of the functional side of the garrison’s functioning, i.e. the performance of permanent military service, with sentry duty at the forefront, concern for the training of entire units and individual soldiers, as well as keeping them in properly subordinated and disciplined. Such conditions were not fulfilled in the case of almost all of cavalry of the so-called ‘national enlistment’ (‘autorament narodowy’).It looked better in the so-called foreign authority (‘autorament cudzoziemski’), especially in the case of infantry units that formed garrisons, the vast majority of them urban. This study attempts to establish in which towns in the Polish-Lithuanian Commonwealth there were garrisons and characterises the most important ones. It also defined and characterised the main problems associated with the existence of the military garrison between 1717 and 1763. These were: - the scope of authority of military commanders (garrison commanders) and the resulting disputes with magistrates; - the maintenance of military infrastructure: the main guardhouse, other guardhouses and military posts, detention centres and others; - issues relating to living conditions, especially the accommodation of soldiers and the consequent obligations of the town and the owners of houses and inns; the provision of food and fuel for the army; sanitary and medical care; the exchange of money; - relations between soldiers and the civilian population.