Arjuna, the Military General
When the eldest Pandava, viz. Yudhisthira became king, Arjuna, and his brothers Bhima, Nakulaand Sahadeva became military chiefs. As a military general, Arjuna led two crucial military campaigns for Yudhisthira. The first one was for the Rajasuya Yajna and another was for the Ashwamedha Yajna.
During the military campaigns that preceded the Rajasuya Yajna (project / sacrifice) of kingYudhisthira, Arjuna was sent to the northern regions where as his brothers were sent to other directions. The mighty mace-fighter Bhima was sent to the east well known for elephant warfare and mace-fight. Nakula and Sahadeva who were skilled in sword fight were sent to the west and to the south. Southerners and Westerners were well versed in sword fight. Arjuna was sent to the north since the foremost of archers were found in the north. He fought with the tribes of Yakshasand Kimpurushas in Tibet. He also traversed through a route that lead him to Simhapura, a city of the Kambojas and to the silk route which passed through modern day Leh (then known as Loha). He also reached the Uttarakuru territory, which is speculated as the same as or close to the territory of the Devas with Indra as their king. This territory was also known as Harivarsha.
During the Aswamedha military campaign, Arjuna went to western and eastern regions. In the west he defeated the kingdoms like Sindhu (Sindh) ruled by Jayadratha's son and Gandhara(north-western Pakistan) ruled by Sakuni's descendants.(take that Mamujaan😆) In the east he reached Anga and Vanga(Bengal) as well as the kingdom of his own son Vabhruvahana situated in southern-Kalinga(southern-Orissa and northern-Andhara_Pradesh).