Siesikai is a township in Aukštaitija, ca. 20 km west of Ukmergė. In World War One it was passed through in late August 1915 by squadrons of 4. Kavallerie-Division deploying east to take part in the encirclement of Vilnius, which fell on September 18.
During the German withdrawal from the East, Red Army units came to Siesikai area ca. January 12, 1919 after previously moving into Ukmergė on January 10. During a sequence of local battles stretching from K?dainiai to Ukmergė, Siesikai was entered by Lithuanian regulars on March 24, 1919.
In the czarist period Siesikai had had a post office (Sesiki) but none during the war. A mandate as įgaliotinis to set up a Lithuanian post office was issued, as from January 1, 1920, to Mykolas Švagžlys who had previously been appointed postmaster of Širvintos (or Širvintai) but had to evacuate when, following Marshal Pilsudski’s ideas of a greater Poland, Širvintos was occupied by Polish troops on May 27, 1919.
When the Lithuanians regained a section of the Vilnius district in the second half of 1920, Mykolas Švagžlys was appointed postmaster of Švenčionėliai as of September 16 and was replaced at Siesikai by Fabijonas Sčikna[s?].
For stamps, Siesikai was supplied with Fourth Berlin Issue followed by the Sėjėjas Issue etc. Early cancelling was done in manuscript, showing place and date. As yet, no other provisional markings have been noted.
A standard calendar-type postmarker was supplied in 1922 or earlier.
Known provisional markings:
Cancelling in manuscript:
1 / III 1920 single, Berlin IV 30 [colln. Doniela]