Google and Facebook were among the top US web destinations in July, according to a new Total Internet Audience metric from Nielsen. The study incorporates hybrid audience measurement data to provide insight into online activity.

For the month of July, 172.5 million unique US people visited Google and stayed for an average of nearly 1 hour 30 minutes. Facebook use was slightly lower at 158.9 million unique, but each user stayed on the site for over five hours.

Yahoo wasn’t far behind Facebook with 148.5 million unique visitors and an average of 2 hours 14 minutes per user. The metrics between Google and Yahoo are interesting, as Google had nearly 25 million more visitors but Yahoo kept users around for roughly 45 minutes longer.

The trio of MSN, Windows Live and Bing just missed the podium with 131 million unique visitors spending just over one and a half hours on the combined destinations. YouTube ranked fifth with 125.9 million visitors.

The biggest dropoff in traffic started with sixth-ranked Microsoft which had over 30 million fewer visitors than YouTube.

These are all impressive figures as Nielsen reports that 213 million Americans were active on the Internet in July 2011. Internet access through home and work PCs was polled at 249 million unique individuals for the same time period. Further stats show that the average American viewed 2,576 web pages and was online for over 27 hours over the course of the month.

Because Nielsen is using hybrid audience measurement data that extends beyond home and work PCs, data for July cannot be trended or compared with previous months’ Total Internet Audience data.