Why did Buenos Aires become Argentina’s federal capital in 1880?

The designation of Buenos Aires as the federal capital of Argentina in 1880 was the culmination of a long-standing power struggle between the city and the interior provinces regarding the nation's political structure.12

For decades, the status of Buenos Aires remained a point of contention, as the city often exerted central authority while the interior provinces sought autonomy. Following the presidential election of Julio Argentino Roca in 1880, a rebellion broke out in Buenos Aires in opposition to his candidacy. Once the national government successfully suppressed this uprising, the perennial conflict over the city's status was finally resolved.3214

To settle the issue, the government converted the city of Buenos Aires into a federal territory and officially established it as the national capital. Consequently, the province of Buenos Aires was required to designate a new capital city, which was established at La Plata.14