Most good library catalogues will allow you to narrow a search by date.

For example, on the British Library main catalogue (which is one of the most extensive available anywhere, and ought to allow you to do useful searches in most English language fields even if, for instance, you will be actually using an American library) you can go to the advanced search option and select not only material type but also start and end dates by year of publication. Thus you can narrow the search you make to books published in the period starting in 1800 and ending in 1899.

Google Books is far from a complete or properly catalogued resource, but it is also possible to do quick-and-dirty searches using this resource in a similar way. Go to the Google Books mainpage, enter a search, and once the results come up you can then select "tools" from under the search bar (the option doesn't show up till after you make a search), then click on the "Any time" option. This brings up a menu that allows you to select a century's worth of publication dates, or enter a custom range.

Here is how you build that faceted search in WorldCat, the world's biggest mass library catalog. This can be accessed by the "advanced search" page. First, find your proper Library of Congress subject heading (in this case, the wildly creative "United States -- History") and then put in your year range, so I did 1800 for the start and 1899 for the end, and ploop, you've got a pretty comprehensive list of American history books published in the 1800s. :)