The neighborhood in Yancheng with the most residents is the central district, specifically the area surrounding the city center. This is primarily due to the concentration of government offices, commercial centers, and public amenities, which attract a large population seeking employment opportunities, education, and access to services. According to the latest census data from 2020, the central district of Yancheng has a population of approximately 300,000 residents, which is significantly higher than other neighborhoods in the city.

The central district's strategic location and infrastructure development have played a crucial role in its population growth. The city center is well-connected by a comprehensive transportation network, including major roads, bus lines, and a railway station, making it easily accessible for both residents and visitors. This connectivity has facilitated the growth of businesses and industries, leading to job creation and attracting a diverse workforce.

Moreover, the central district boasts a variety of residential complexes, ranging from affordable housing to upscale apartments and condominiums. The availability of different housing options caters to the needs of various income groups, contributing to the high population density. Additionally, the central district is home to numerous schools, hospitals, and recreational facilities, further enhancing its appeal as a desirable place to live.

The central district's vibrant commercial scene also contributes to its popularity. The presence of shopping malls, markets, and restaurants offers residents a wide range of amenities, making it convenient for daily living. The bustling atmosphere and cultural activities, such as festivals and events, add to the neighborhood's charm and appeal.

In conclusion, the central district of Yancheng is the neighborhood with the most residents due to its strategic location, infrastructure, and amenities. The combination of employment opportunities, housing options, and access to services has made it a preferred choice for many, resulting in a high population density.