The exact location of Pilėnai is unknown and historians propose many different locations.
Annalista Thorunensis and Wigand of Marburg mentioned that it was located in Trapėnai land (terra Troppen) but its location is also unknown.

Maciej Stryjkowski (1547–1593) identified Punia as the location of Pilėnai (54°30′43″N 24°05′25″E).
This opinion, while not based on any historical arguments, spread widely to historical works and was popularized by various works of fiction.
Punia hill fort became known as Margiris Hill and in 1973 a monument was erected in memory of Margiris (the monument is inscribed with four lines from a poem by Maironis).
The town organizes events to commemorate the events of 1336.

Based on superficial etymological connections, Teodor Narbutt identified Pilėnai with Pilionys (Naujaupis) hill fort in the Kėdainiai District (55°29′12″N 23°47′49″E) and Jonas Basanavičius with Piliakalniai hill fort in the Vilkaviškis District (54°27′56″N 23°02′52″E).
Zenonas Ivinskis searched for Pilėnai along the lower reaches of the Neman River.
He agreed with Kazys Paunksnis and identified Pilėnai with the Pypliai hill fort near the confluence of Nevėžis and Neman (54°55′38.5″N 23°45′02″E).

Alvydas Nikžentaitis focused on the location of Trapėnai and determined that it was a triangle between Viešvilė, Ančia River (tributary of Šešuvis), and Veliuona.
Further, he paid particular attention to Ycoine mentioned by Jean d'Outremeuse in connection with Margiris' duel with King John of Bohemia in 1329 and identified it with Jūkainiai village in the Raseiniai District.
There are five hill forts within a 10 km (6.2 mi) distance from Jūkainiai, including the Molavėnai-Graužai hill fort (55°26′52.5″N 22°52′07″E).
In 1995, Gintautas Zabiela organized a survey of these hill forts and determined that one of them is likely not even a hill fort and other three, including Molavėnai, lacked sufficient cultural layer and archaeological artifacts.
An archaeological excavation of Molavėnai outer bailey in 2009 found only a few minor items (fragments of clay pots, pieces of iron, stone grinders) that are dated to the 1st–5th century.
Excavation of 10 m² (110 sq ft) of the upper bailey produced no artifacts but revealed up to 1.5 m (4 ft 11 in) thick layer of clay (cf.
earthen floor) used to increase hill fort's height which would date it to the second half of the 14th century.

According to Zabiela's survey in 1995, the fifth hill fort, Ižiniškiai (55°24′24.6″N 22°48′53″E), is now severely damaged by erosion and human activities but was a strong hill fort with a large settlement.
Zabiela surveyed additional six hill forts in 1996, including Ivangėnai-Karšuva hill fort near Skaudvilė (55°25′19″N 22°36′16″E) but concluded that Ižiniškiai remained the most probable location of Pilėnai.
Tomas Baranauskas disagreed with Nikžentaitis' analysis and searched for Pilėnai in the area of five hill forts that, according to Guillaume de Machaut, were captured by the Teutonic campaign to Medvėgalis in 1329.
He concluded that Pilėnai stood in Pilės hill fort near Kaltinėnai in Tauragė District (55°34′1″N 22°26′01″E).
However, an excavation of 8.5 m² (91 sq ft) area in 1990 produced no artifacts.

Bilionys hill fort in the Šilalė District (55°35′49″N 22°19′17″E) was first suggested by German historian Johannes Voigt.
This version is supported by Stasys Kasparavičius who noted that Bilionys is sometimes known as Pilionys and is very similar to Pillenen mentioned in written sources.
Additionally, Bilionys is located just 6 km (3.7 mi) south of Medvėgalis which was attacked in 1329 and also likely defended by Margiris.
Bilionys must have been a large and strong fortress as its upper bailey 57 m × 37 m (187 ft × 121 ft) but there is no mention in written sources that it was attacked while neighboring hill forts were attacked several times.
However, etymological connection between Bilionys and Pilėnai is dubious as the toponym Bilionys likely derived from a personal name.
Nevertheless, since 2012 Verkiai Regional Park organizes events to commemorate Pilėnai on Bil
The exact location of Pilėnai is unknown and historians propose many different locations. Annalista Thorunensis and Wigand of Marburg mentioned that it was located in Trapėnai land (terra Troppen) but its location is also unknown. 
Maciej Stryjkowski (1547–1593) identified Punia as the location of Pilėnai (54°30′43″N 24°05′25″E). This opinion, while not based on any historical arguments, spread widely to historical works and was popularized by various works of fiction. Punia hill fort became known as Margiris Hill and in 1973 a monument was erected in memory of Margiris (the monument is inscribed with four lines from a poem by Maironis). The town organizes events to commemorate the events of 1336.
Based on superficial etymological connections, Teodor Narbutt identified Pilėnai with Pilionys (Naujaupis) hill fort in the Kėdainiai District (55°29′12″N 23°47′49″E) and Jonas Basanavičius with Piliakalniai hill fort in the Vilkaviškis District (54°27′56″N 23°02′52″E). Zenonas Ivinskis searched for Pilėnai along the lower reaches of the Neman River. He agreed with Kazys Paunksnis and identified Pilėnai with the Pypliai hill fort near the confluence of Nevėžis and Neman (54°55′38.5″N 23°45′02″E). 
Alvydas Nikžentaitis focused on the location of Trapėnai and determined that it was a triangle between Viešvilė, Ančia River (tributary of Šešuvis), and Veliuona. Further, he paid particular attention to Ycoine mentioned by Jean d'Outremeuse in connection with Margiris' duel with King John of Bohemia in 1329 and identified it with Jūkainiai village in the Raseiniai District. There are five hill forts within a 10 km (6.2 mi) distance from Jūkainiai, including the Molavėnai-Graužai hill fort (55°26′52.5″N 22°52′07″E). In 1995, Gintautas Zabiela organized a survey of these hill forts and determined that one of them is likely not even a hill fort and other three, including Molavėnai, lacked sufficient cultural layer and archaeological artifacts. An archaeological excavation of Molavėnai outer bailey in 2009 found only a few minor items (fragments of clay pots, pieces of iron, stone grinders) that are dated to the 1st–5th century. Excavation of 10 m² (110 sq ft) of the upper bailey produced no artifacts but revealed up to 1.5 m (4 ft 11 in) thick layer of clay (cf. earthen floor) used to increase hill fort's height which would date it to the second half of the 14th century. 
According to Zabiela's survey in 1995, the fifth hill fort, Ižiniškiai (55°24′24.6″N 22°48′53″E), is now severely damaged by erosion and human activities but was a strong hill fort with a large settlement. Zabiela surveyed additional six hill forts in 1996, including Ivangėnai-Karšuva hill fort near Skaudvilė (55°25′19″N 22°36′16″E) but concluded that Ižiniškiai remained the most probable location of Pilėnai. Tomas Baranauskas disagreed with Nikžentaitis' analysis and searched for Pilėnai in the area of five hill forts that, according to Guillaume de Machaut, were captured by the Teutonic campaign to Medvėgalis in 1329. He concluded that Pilėnai stood in Pilės hill fort near Kaltinėnai in Tauragė District (55°34′1″N 22°26′01″E). However, an excavation of 8.5 m² (91 sq ft) area in 1990 produced no artifacts.
Bilionys hill fort in the Šilalė District (55°35′49″N 22°19′17″E) was first suggested by German historian Johannes Voigt. This version is supported by Stasys Kasparavičius who noted that Bilionys is sometimes known as Pilionys and is very similar to Pillenen mentioned in written sources. Additionally, Bilionys is located just 6 km (3.7 mi) south of Medvėgalis which was attacked in 1329 and also likely defended by Margiris. Bilionys must have been a large and strong fortress as its upper bailey 57 m × 37 m (187 ft × 121 ft) but there is no mention in written sources that it was attacked while neighboring hill forts were attacked several times. However, etymological connection between Bilionys and Pilėnai is dubious as the toponym Bilionys likely derived from a personal name. Nevertheless, since 2012 Verkiai Regional Park organizes events to commemorate Pilėnai on Bil
Pilėnai