Social Explorer is a web-based mapping and data visualization tool. Access is provided by the Yale University Library to everyone at Yale. Explore over 500,000 data indicators and over 220 years of data for the United States from present to 1790, including all Decennial Censuses, American Community Surveys and many other datasets.
These resources are meant as starting points for your research. Keep in mind that statistics at the neighborhood level are not available consistently across the entire United States, and that some datasets and statistical publications may not be produced on an annual basis. If you aren't finding what you need with these databases, a good next step is to find out if there's a local government agency that compiles this data, and either use the agency's online tools or publications, or contact the agency directly to find out if they will make their data available to you.