In WWI, Vilkija (Vilki, Wilki) was taken by German troops during their preparations in the summer of 1915 to storm Kaunas (Kovna, Kovno, Kowno) whose formidable fortress endangered the German advance further east. At Vilkija, a bridge across the river Nemunas (Njemen) was built in late July to facilitate the movement of troops. The fortress of Kaunas was finally taken on August 18, 1915.
Though Vilkija had had a post office in czarist times, no such facility was established during the German occupation, also no stationary Feldpost. When the German army retreated from Russia at the end of 1918, Vilkija for a while was militarily deserted, though later German voluntary border guards (Grenzschutz) set up a post supervising the river transport on the Nemunas between Kaunas and the Memelland. For their postal needs the guards used Frw. Feldpost 728 stationed in Kaunas.
A postmaster (įgaliotinis) to open a Lithuanian post office at Vilkija, Valerijonas Miliauskas, was appointed by Pašto Valdyba as early as January 1, 1919, though the actual opening date is not known. Despite some health problems he was still in charge at the end of 1920. Vilkija was also included, as a stop, when carrying mail by steamer between Kaunas and Jurbarkas began, formally, as from May 14, 1919.
Early stamps noted from Vilkija come from Fourth Berlin Issue, though W.E. Norton reported a 10 sk. value from Second Berlin Issue.
In the absence of a formal postmarker, early cancelling was done by using a two-line rubber cachet whose top line contained the date and the bottom line “VILKIJA”, but the specific day was written in by hand. W.E. Norton had a stamp from Vilkija which was additionally pen-cancelled cross-wise.
In the second half of 1919 Vilkija acquired a relatively large double-boxed cachet with “Vilkija” as the top line and the date without the year as the bottom line. It was still in use at least in early 1920.
Early mode of indicating registration is not known, but by early 1920 Vilkija was supplied with a standard registration cachet.
Known provisional cancelling:
Two-line small cachet with the day in ink:
1 III 1919 (?) [reported by Fugalevičius]
29 IV 1919, single, Berlin IV 50 [colln. Doniela]
1 VII 1919, single, Berlin IV 30 [formerly Norton]
no date, single, Berlin II 10, also cancelled cross-wise [formerly Norton]
no date, single, Berlin IV 30 [colln. Doniela]
no date, single, Berlin IV 60 [formerly Norton]
Two-line large double-boxed cachet, no year:
26 XII  letter to USA undelivered, Berlin IV 60 [fomerly Matuzas]
6 II  letter to France reg. No. 223, Berlin IV 60 x2 [colln. Lapas]