The capture of Paysandú was a significant event within the Uruguayan War, which pitted various factions against one another in a struggle for control over Uruguay. The siege began when Brazilian and Colorado forces aimed to neutralize the Blanco faction's stronghold in Paysandú. The Brazilian army, motivated by the desire to expand its influence and support the Colorado forces aligned with them, laid siege to the city. The resistive Blanco defenders held out for several months through a combination of fortified positions and strategic counterattacks. However, logistical challenges and dwindling supplies severely crippled their capability to sustain the defense.

The siege had escalated tensions across the wider region, with nearby factions watching closely as the outcome could signify shifting allegiances and power dynamics. By January 1865, the situation had become untenable for the defenders as the Brazilian forces, supported by their Colorado allies, initiated a final assault. On the second of January, they breached the last defenses and took control of the city, effectively ending the siege. This marked a pivotal moment not only for Paysandú but also in the larger context of the Uruguayan conflict, contributing to the eventual rise of the Colorado faction.

The capture of Paysandú was followed by significant repercussions for the remaining Blanco forces as it further diminished their territorial control. The city served as a crucial point for supply and troop movements, with its fall effectively consolidating the opposing forces' strength in the region. The battle highlighted the intensity of the political divisions in Uruguay regarding power and governance, showcasing the implications of external influences such as Brazil’s involvement in domestic disputes.