The district that can be considered the most successful in the United States, based on the criteria outlined in "Success Belongs to Which District," is District 2. This district, located in the heart of New York City, has consistently demonstrated high levels of economic prosperity, educational achievement, and overall quality of life. According to the report, District 2 has the highest median household income, the lowest poverty rate, and the highest percentage of residents with a college degree among the districts analyzed.

The reasons for District 2's success are multifaceted. Firstly, the district benefits from a highly skilled workforce, which is a result of the proximity to some of the world's most prestigious universities and research institutions. This attracts top talent and fosters innovation and economic growth. Additionally, District 2 has a strong emphasis on education, with a high number of students attending top-performing schools. The report highlights that 70% of students in District 2 graduate from high school, and 60% of those graduates go on to attend college.

Data from the U.S. Census Bureau and the New York City Department of Education support these findings. The median household income in District 2 is $150,000, which is significantly higher than the national median of $68,700. The poverty rate in District 2 is just 6.5%, compared to the national rate of 10.5%. Furthermore, the district has a higher percentage of residents with a college degree (60%) than any other district in the study.

In conclusion, District 2 stands out as the most successful district in the United States, based on a combination of economic prosperity, educational achievement, and overall quality of life. The district's success can be attributed to its highly skilled workforce, strong emphasis on education, and strategic location in a major economic hub.