Ōta-ku was established on March 15, 1947, through the merger of the former Ōmori and Kamata Wards, combining their distinct historical identities and economic foundations.

Situated in the southernmost part of Tokyo, Ōta-ku borders Kanagawa Prefecture across the Tama River and boasts a significant coastline along Tokyo Bay, making it a crucial maritime gateway.

Home to Tokyo International Airport (Haneda Airport), Ōta-ku serves as Japan's busiest domestic and one of its major international airports, facilitating immense passenger and cargo traffic.

With a population exceeding 740,000 residents as of recent estimates, Ōta-ku holds the distinction of being Tokyo's most populous special ward.

The ward has experienced steady population growth since its post-war reconstruction, attracting both families and businesses due to its excellent transportation links and diverse employment opportunities.

Ōta-ku is renowned as a hub for small-to-medium manufacturing enterprises (SMEs), particularly those specializing in precision machinery, metalworking, and advanced components, contributing significantly to Japan's industrial base.

These highly skilled SMEs in Ōta-ku are a driving force for technological innovation, often collaborating with larger corporations and research institutions on cutting-edge projects.

Ikegami Honmon-ji Temple, a significant Nichiren Buddhist temple founded in 1282, stands as a major cultural landmark in Ōta-ku and hosts the annual Oeshiki Festival, attracting hundreds of thousands of visitors.

The Oeshiki Festival at Ikegami Honmon-ji, held every October, commemorates the death of Nichiren, featuring a vibrant procession with Mando (decorative lanterns) and traditional music.

Ōta-ku is also known for its local hot springs, particularly the "Kuroyu" (black hot water) onsen, which are unique due to their high content of metasilicic acid, offering a traditional Japanese bathing experience.

During the Edo period, parts of Ōta-ku, especially the Ōmori district, were significant as a post town (shukuba) on the Tōkaidō road, a crucial route connecting Edo with Kyoto.

The presence of Haneda Airport underscores Ōta-ku's vital role as the primary aerial gateway for visitors and business travelers entering Japan, linking the capital directly to numerous global cities.

The ward boasts several extensive green spaces and parks, such as Heiwa-no-Mori Park and Nishikamata Park, providing recreational areas and contributing to the residents' quality of life.

Ōta-ku hosts various educational institutions and vocational schools, supporting the development of skilled labor crucial for its specialized manufacturing industries.

While Ōta-ku does not contain any UNESCO World Heritage Sites, its rich history, industrial prowess, and cultural heritage, particularly around Ikegami Honmon-ji, contribute significantly to Tokyo's diverse appeal.