The “Libertarian” ideology of the U.S. Libertarian Party is basically an unusually doctrinaire form of economic liberalism. I’m more hesitant to say it’s socially liberal, at least insofar as it doesn’t seem to permit dissent from established hierarchies. They play lip service to getting the government off people’s backs in the social sphere, as a matter of personal freedom (a trait of liberalism) rather than as a matter of simply limiting the institutional power of government (conservatism), but they tend to break for the latter or even sacrifice that value entirely in favor of what they, rather misguidedly I might add, think is in the interest of their pocket books.
Also, to be fair, there are about two meaningful ways to use the term “libertarian.” One is in reference to a political philosophy (anarchism, or at least a wing of anarchism), and the other is the flip side of a dichotomy, with libertarianism being the opposite of authoritarianism. Given how authoritarian and hierarchical the Libertarian Party is, their use of the term at all in either sense is a tad comical.
Finally, don’t fall for the Republicans-are-conservative, Democrats-are-liberal trap. Neither party breaks elegantly along those lines, but the Democrats arguably hew reasonably closely to conservatism far better than the Republicans hew towards liberalism. It’s Democrats who try to preserve the status quo at any cost (conservatism), and Republicans who try to break it in favor of radical change (at least arguably liberalism).