From the river area where the municipality originated, the land rises gradually, culminating in the Malmasín mountain (361 m), on the border with Arrigorriaga.

Its proximity to the mines of Ollargan, Morro and Miravilla, and those of the Basauri-Galdakao Group, caused an increase in the municipality's population.

Thereafter, it remained the largest population center and municipality in the district of San Miguel de Basauri until 1902, when the transfer of the town hall to Arizgoiti was approved.

Thousands of families from all regions of Spain provided Basauri with new people and buildings, radically changing its image and urban landscape.

Toponyms in Basauri include Ariz, Arizgoiti, Arizgain and Arizbarren (Azbarren) Basozelai, Etxerre, Sarratu, Urbi, Bizkotxalde (Beaskoetxealde) Pozokoetxe, Pagobieta, Iruaretxeta, Artundoaga, Abaroa, Gaztañabaltza, Uriarte, Errekalde, Lapatza, Arteaga, Arteagagoitia, Uribarri, Kalero, Bidebieta, Soloarte, Ugarte, Kantarazarra, Iturrigorri, Elexalde.

Bidebieta appears as Dos Caminos (Two Roads) at the train station, resulting in a popular misconception that this was the original name of the town.

Although some authors believe this to be a Castilian translation of Kareaga, its name refers to the fact that a holding of limestone for the manufacture of lime was located in this area; such places are called 'Calero' in Spanish.

Symbols of the festival include a local character, the Escarabillera [es], and zurracapote, the typical drink, which is prepared by the fifteen crews belonging to the cultural association Herriko Taldeak, served to participants in a jug.

Zurracapote is a drink similar to sangria, made with red wine, lemon, cinnamon, liquor, sugar and condiments.

The Escarabillera is a character based on the women and men who, in Basauri (as in many other municipalities) went, in times of great need at the beginning of the 20th century, to the tracks where the steam trains ran or to the dumps of the foundry companies (La Basconia) in search of coal that had not been entirely burnt (called escarabilla).

The escarabillera walks from the start of the festival until the end, when it is released into the air attached to balloons with a message written in several languages, with the hope that someone will recover it.

Until the industrial transformation of the late 19th century, Basauri was a purely agricultural area where corn was grown and pasture for cattle and sheep were harvested, and there were some flour mills.