It is generally considered to begin in the Tengger mountain range and extend eastwards to the east coast of Java.

Anthropologist Robert W. Hefner considered the western boundary of the region to be just east of the modern-day Malang-Surabaya highway.

[2] Unlike Java's central heartland and northern coast, the region is drier, more rugged, and lacks major rivers.

As the cradle of Javanese civilization blossomed in the ninth century in Progo and Opak River valley in Central Java during Mataram kingdom, later shifted east to Brantas River valley during Kediri, Singhasari and later Majapahit Kingdom circa fourteenth century.

As the reward of Wiraraja's support, in 1295, Raden Wijaya agreed to give him the eastern salient of Java, which includes Blambangan areas with Lumajang as its capital.

For almost three centuries, Blambangan was situated between two different political factions, the Islamic state of Mataram in the west, and various Hindu realms in Bali (Gelgel, Buleleng, and Mengwi) in the east.

[8] For most of the modern era, the eastern salient lay outside the control of Javanese political powers, which were typically based in Central Java.

[11] It remained outside Mataram's influence between the seventeenth to nineteenth centuries, when that region was developing the features and characteristics known today as essentially Javanese.

[15] The Dutch attempt to establish control was met by resistance, including from people calling themselves "descendants of Surapati".

This includes the Tenggerese sub-ethnic group who live in the Tengger mountains[20] and the Osing subgroup in the easternmost Banyuwangi regency.

[11] In contrast to the social hierarchy of Central Java, the eastern salient maintained its frontier character, populist mannerism, and less hierarchical ways, which remain to the present day.

[2] Because of steady migration from the island of Madura off the eastern salient's north coast, the Madurese also inhabit the area.