During the interwar period, Lithuania regained independence. The first law on administrative sub-units was passed on July 1, 1919. It declared that Lithuania was divided into twenty counties (Lithuanian: singular – "apskritis", plural – "apskritys"). Several more counties (including Zarasai, Naujieji Švenčionys, Vilnius, Eišiškės, Lida, Ashmyany and Hrodna) were reserved for territories in the Vilnius Region, that Lithuania had claims to, but were under Polish or Russian control. Later on Suwałki county was lost to Poland, but Zarasai (also known as Ežerėnai) county was acquired. Two of the designated counties, Trakai and Sejny, had their proclaimed capitals outside the "de facto" borders of Lithuania and had their temporary capitals established at Kaišiadorys and Lazdijai. After the Klaipėda Region was acquired in 1923, it was divided into three counties (Klaipėda, Šilutė and Pagėgiai). That way the number of counties increased to twenty three and remained stable until 1939. According to a law passed in 1931 eleven first-class cities became independent of county administration and had their own government. In March 1939, after an ultimatum from Hitler, Lithuania lost the Klaipėda Region with its three counties. In October Soviet Union returned one fifth of the Vilnius Region in exchange for Red Army stations in Lithuania. Acquired Vilnius Region was divided into three counties (Vilnius, Eišiškės, and Naujieji Švenčionys). Therefore, at the end of 1939 Lithuania again had twenty three counties. Counties were further subdivided into townships (Lithuanian: singular – "valsčius", plural – "valsčiai"). In 1933 there were 365 townships. The townships were further subdivided into elderates (Lithuanian: "seniūnija").