More than half appear to be in New York. Others are in Washington, Virginia and Los Angeles.

Why are so many investigations in New York?

Mr. Trump worked in New York for years and ran his campaign from here. That puts the president, his associates and his company, the Trump Organization, in the jurisdiction of New York investigators.

Who is investigating in New York?

• On the federal level: the Southern District of New York and the Eastern District of New York.

• On the state level: the attorney general, the Manhattan district attorney, the Department of Financial Services and the Department of Taxation and Finance.

What are they investigating?

A lot. Mr. Trump’s business, his campaign, his inauguration and his presidency.

They are mostly following his money: where it went and how it was accounted for.

One set of inquiries relates to Mr. Trump’s campaign and other activities. Did his business arrange payments to women who claimed they had affairs with Mr. Trump, which may violate campaign finance rules?

Did Mr. Trump’s inaugural committee make false filings with the Federal Election Commission? Did the committee receive illegal donations? Did a top campaign and inaugural committee fund-raiser use his connections to the president to bolster his own businesses?