In a post earlier today I made a distinction, that being in the United States illegally is a civil matter, not a criminal one, and thus inappropriate to label such people criminals. 

A comment from linseel shows that I had misunderstood a crucial distinction:

"The distinction is between *being* here illegally -- overstaying a visa, for instance -- and *entering* illegally. Illegal entry is a criminal offense." 

And the comment from linseel cited the relevant passage from the U.S. Code, Title 8, Section 1325. 

Of course I looked. Here it is:

Sec. 1325. Improper entry by alien


    (a) Improper time or place; avoidance of examination or inspection;

      misrepresentation and concealment of facts

      Any alien who (1) enters or attempts to enter the United States

    at any time or place other than as designated by immigration

    officers, or (2) eludes examination or inspection by immigration

    officers, or (3) attempts to enter or obtains entry to the United

    States by a willfully false or misleading representation or the

    willful concealment of a material fact, shall, for the first

    commission of any such offense, be fined under title 18 or

    imprisoned not more than 6 months, or both, and, for a subsequent

    commission of any such offense, be fined under title 18, or

    imprisoned not more than 2 years, or both.