used with cities, towns, small islands (small as in small enough to contain just 1 city, aka not Sicily), hills of rome, humus, domus, rus
1st/2nd declension singular - same as genitive
1st/2nd declension plural - same as dative = ablative
3rd declension singular - both dative -i and ablative -e are used
3rd declension plural - same as dative = ablative