Here are the main theories:
- Folkloric name for a bend in Akerselva: Originally Kuba was just a folk name for a little vik (a bend or bay) in the Akerselva by Bergverksgata, and over time it became the accepted name for the green area on both sides of the river.
- Reference to the Spanish–American War (1898): Around the turn of the 20th century, this kind of local nickname appeared elsewhere in Norway (in towns like Bergen and Bærum) — linked to the Spanish–American War of 1898. In that war the Caribbean island of Cuba was at the center of global attention, and Norwegian newspapers and sailors often spoke about it. Some historians think local kids or residents began calling this rough area near Akerselva “Cuba” as a sort of tongue-in-cheek label — perhaps connecting the place with the “Wild West/foreign” feel of the era, especially as nearby Grünerløkka had its own nickname “Ny York.”
- A simplification of Kudskebakken: There’s also a theory that the name evolved from the word Kudskebakken, an old place name seen on maps from the 18th century. Kudskebakken may have been associated with a tavern or resting place for horse-drawn wagons in the area — and over time “Kudskebakken” could have been contracted in everyday speech to Kuba.
- Other suggestions (less likely): Some people once thought the place name came from a gassklokke (gas holder) that once stood nearby, or by association with the geometric kube, but these explanations are generally considered weaker because the word Kuba occurs in local usage before the gasworks was built.
In short: there’s no single proven origin, but the strongest explanations tie the name to folk naming of the river bend and to late 19th-century cultural references, possibly linked to the Cuban island and playful street naming around Grünerløkka.