Great that you bring this one up again, Jesper, since this was the
very first question I asked here at BP. Never got an answer as far as
I can remember, but it is difficult to find anything comprehensive on
PLRU.

But anyway, I have done some research and have found the "Border
treaty" (if it can be called a border treaty, because it is very
vague indeed) of 1945. Now this was prior to demarcation, of course.
And the border in question (the one that divided East Prussia,
nowadays PLRU) was only provisionally established, pending a peace
treaty (that never came). In 1958, the boundary was made "official"
after all.

The treaty (translation mine, and maybe not 100% accurate):

Boundary agreement between Poland and the USSR

Moscow, 16 august 1945

The president of the State People's Council of the Polish Republic
and the Presidium of the People's Council of the Union of Socialist
Soviet Republics, in their desire to regulate the matter of the state
boundary between Poland and the Union of SSR in a spirit of
friendship and unity, have thereto reached the present Agreement and
have named as their plenipotentiaries:

The President of the State People's Council of the Polish Republic
the Chairman of the Council of Ministers of the Provisional
Government of National Unity, Edward Osóbka-Morawski,

The Presidium of the Supreme Soviet of the Union of Socialist Soviet
Republics the Vice-Chairman of the Council of People's Commissars
and the People's Commissar of Foreign Affairs of the USSR, V. Molotov,

who, at the exchange of their powers found them in the appropriate
form and in good order, have agreed to the following:

Art. 1

To establish, in accordance with the decision made during the Crimean
Conference, the state boundary between the Polish Republic and the
Union of SSR as following the "Curzon line" with deviations from it
in some areas of five to eight kilometres, to the advantage of
Poland, according to the annexed map with a scale of 1:50000,
additionally ceding to Poland:

a) an area east of the "Curzon line" up to the Western Bug and
So³okija rivers, north of the town of Kry³ów, ceded to Poland and not
exceeding thirty kilometres,

b) a part of the Bia³owie¿a wilderness, in the area of Niemirów-
Ja³ówka, situated east of the "Curzon line", including Niemirów,
Hajnówka, Bia³owie¿a, and Ja³ówka, ceded to Poland and not exceeding
17 km.

Art. 2

In accordance with the first article, the state boundary between the
Polish Republic and the USSR will run along the following line:

From a point, situated approximately 0.6 kilometres to the south-west
of the source of the river San, to the north-east in the direction of
the source of the river San, and further along the river San,
following its stream to a point south of the settlement Solina,
further to the east of Przemyl, west of Rawa Ruska, to the river
So³okija, from there along the river So³okija and the river Western
Bug to Niemirów-Ja³ówka, leaving on the Polish side the part of the
area of the Bia³owie¿a wilderness mentioned in the first article, and
from there to the meeting point of the boundaries of the Polish
Republic, the Lithuanian SSR, and East Prussia, leaving Grodno on the
USSR side.
The demarcation in the terrain of the boundary described in the
present article will be executed by a mixed Polish-Soviet commission
seated in Warsaw, which will start its work not later than 15 days
after the exchange of the ratification documents.

Art. 3

Until the definitive agreement on territorial matters by a peace
agreement, the part of the Polish-Soviet boundary up to the Baltic
sea will, in accordance with the decision taken during the Berlin
Conference, run along a line from a point on the eastern shore of the
Gulf of Gdañsk, depicted on the annexed map, to the east, north of
the town Braunsberg Goldapp to a point where this line meets the
boundary line described in the second article of the present
agreement.

Art. 4

The present agreement is subject to ratification, which has to be
done as soon as possible. The agreement comes into force from the
moment of the exchange of the ratification documents, which will take
place in Warsaw.

Done in Moscow, on August 16, 1945, in two copies, each of them in
Polish and Russian, both having equal powers.

Source: http://www.vilp.de/Plpdf/04/p064.pdf

-----

Here some additional information on the problems back then, also
translated by me, and definitely not 100% accurate, but I think I got
the essence (it is from http://www.opcja.pop.pl/numer11/11lad.html ):

Boundary through the middle of a barn

The present Polish-Russian boundary runs latitudinally from the place
situated on the Polish-Lithuanian-Russian tripoint, which is north-
west of Wi¿ajny, up to the Baltic sea, to the Vistula spit in the
area of Nowa Karczma (Piaski). It was established by the Polish-
Soviet boundary agreement, signed on August 16, 1945, by Edward
Osóbka-Morawski and Vjaèeslav Molotov in Moscow. The length is 210
km. The decision was made by Stalin, Churchill, and Roosevelt during
the Teheran Conference, and was re-enforced by the Potsdam Agreement.
As a consequence of this decision East Prussia became divided in a
Polish part (Warmia and Mazuria), situated to the south of the
mentioned boundary line, and a Soviet part, north of it, first named
Königsberg province, and later by decree of the Presidium of the
Supreme Soviet of the USSR of June 4, 1947 [? I thought it was in
1946 P.S.] Kaliningrad province. It became a Russian detached
enclave on the Baltic sea, bordering only Poland and Lithuania.

The newly established boundary intersected as a straight line roads,
railways, canals, and even single settlements. It broke up an area
that had become a political, geographical, and economical unit within
a century. East Prussia, which existed up to the fall of the 3rd
German Empire, counted 36990 km2. 23802 km2 was added to Poland, to
the USSR 13181 km2.

In both parts, a new administrative division was executed. In the
place of the German Bezirk and Kreis division in the northern part of
the former East Prussia, where the city of Königsberg was situated, a
division of rayons and rayon cities was set up.

"On the territory which was added to Poland the województwo of
Olsztyn was created, and the rest was added to the województwo's
Bia³ystok and Gdañsk. At present the territory is at the borders of
the województwo Warmia-Mazuria, and the western edges in the
województwo of Pomerania.

On August 16, 1946, an agreement between Poland and the USSR was
reached in Moscow on the demarcation of the boundary between the two
countries. However, because of controversies that had arisen on the
exact location of its course, the Polish side decided on an exact
inspection of the boundary in the terrain.

In the summer of 1947, the geodetical services had executed a
comprehensive on-the-spot survey of the entire boundary terrain and
drew this unilaterally established boundary on the Polish maps.
During these activities, they could observe the Soviet defence
system: barriers of barbed wire to keep out, stretching along the
boundary, and warning devices, alerting the guards' station the
moment a human foot or a paw of an animal from the forest would touch
the narrow, guarded boundary strip. () Many times, boundary shifts
although insignificant ones in 1945 and 1946, put one on the alert;
although the boundary wasn't final, it was very possible that with
the next correction a village might find itself within the USSR and
all the efforts of the settlers would go out the window. It was also
found that the boundary line ran between buildings and the fields
belonging to them, or between living quarters and stables. And in
Szczurków it happened that the boundary ran straight through a shed"
writes Bronis³aw Sa³uda from Olsztyn, investigating the question.

------

Peter S.

--- In BoundaryPoint@yahoogroups.com, "Jesper Nielsen" <jesniel@i...>
wrote:

> PLRU seems straight, but looking at a good map will indicate line

drawn with vodka in the blood.