Additionally, the poll finds that Americans' awareness of key elements of the law has declined somewhat since passage when media attention was at its height. For example in April 2010, 64 percent of the public recognized the law would prohibit insurance companies from denying coverage to people with pre-existing medical conditions. That number has fallen to 53 percent today.

The public is equally as confused about what their state is doing about health reform. Just 7 percent of the public say they have heard "a lot" (and 15 percent have heard "some") about their own state's decision to set up an exchange or leave the task to the federal government. And 78 percent say they don't know whether their governor has made a decision about whether to expand Medicaid under the law.

Overall, public opinion of the health care law remains divided, with 40 percent holding an unfavorable view of the law and 37 percent holding a favorable one.

The public's expectations about the law's likely impact on their own families tend to be more negative than positive, with 29 percent saying the PPACA will make them worse off, 21 percent saying it will make them better off, and four in 10 saying it won't make much difference. About half also think their family's health care costs will get worse under the law, while 15 percent say their costs will get better and 33 percent say they will stay about the same.

More Americans also say they favor expanding Medicaid in their state (52 percent) than say they oppose it (41 percent), and a large majority has a favorable view of the law's health insurance exchanges (80 percent), according to the poll.

The Obama administration is beginning to celebrate the law's third anniversary, which takes place this Saturday.

Kaiser Family Foundation surveyed roughly 1,200 adults March 5-10.

Also read: What you might not know about the PPACA