business and corporation records
Each state has an office - usually either the Secretary of State or a Department of Corporations - that requires filings by business partnerships operating in that state.
Information in the filings varies from state to state, but usually they list the address and general partners of a partnership.
Each state keeps an alphabetical index by the names of the partnerships operating in that state.
Many states have websites where you can search the index by the name of a partnership and retrieve some of the information in the filings made by the partnership.
(Note: for more help understanding partnerships and the difference between them and other businesses, check the Help Understanding Different Types of Businesses section of this guide)