Ohio has closed an antitrust investigation into Google's business practices that dates back more than three years, though a probe in Mississippi appears to be ongoing.
The Ohio attorney general's office told Google this past November it was closing the investigation, Google disclosed in a regulatory filing Monday. The investigation was opened in May 2011.
The focus of the investigation wasn't revealed, but Google's dominance in search and online advertising was likely a factor.
Other states including Texas and Mississippi have launched investigations into Google's business practices in the past.
In Texas, the attorney general's office was looking into complaints from companies that Google demoted them in search results or reduced their appeal to advertisers. That investigation, opened in 2010, ended last May.
Mississippi's investigation, however, appears to be ongoing. "We remain willing to cooperate with them if they have any further information," Google said in its filing Monday.
It's still facing scrutiny in several other countries, including Argentina, Brazil, India, Taiwan and Canada. And European regulators are looking at issues related to privacy, search and other areas.
After regulatory pressure In the U.K., Google recently said it would improve how it informs people about the data it collects about them. Meanwhile, members of the European Parliament have proposed separating Google's search engine from other commercial services as one way to resolve competition issues.
Google says it thinks it has adequately responded to the allegations in Europe and that it will continue to cooperate with the European Commission.