They are a semi-nomadic people who live mainly in the northern half of Spain.
They have declined in number from earlier reports and are possibly vanishing as a distinct ethnic group.
The term comes from the word quincallería (ironmongery), from ironmongers who first used this cant as part of their trade.
The mercheros identify as a distinct group separate from the Roma gitanos.
Scholars have many theories about the social origins of mercheros, summarized as the following: