To estimate how many Medicaid applicants are sitting on waiting lists, CQ Roll Call called and emailed officials in all 50 states and the District of Columbia and combined estimates from the 41 that responded as of May 29.

CQ Roll Call asked for the total number of unprocessed applications and the number of people covered, as well as states’ estimates of how many people in line filed duplicate applications.

The survey’s estimate of at least 2.9 million unprocessed applications is a conservative tally because some states didn’t furnish all of the requested information. Nonetheless, the number of those potentially deprived of Medicaid benefits is almost equal to the total populations of Wyoming, Montana and North and South Dakota.

Thirty-six states rely on the federal insurance site healthcare.gov to transmit applications of people federal officials believe will qualify for Medicaid. Six of those states provided CQ Roll Call with the number of applications still stuck at the federal marketplace but couldn’t say how many people were covered. Eleven offered numbers for pending applications that had been transferred but similarly didn’t know the number of individuals covered in the paperwork.

In such instances, CQ Roll Call assumed that each application accounted for a single individual, even though they could actually represent a family.

It’s also important to note that the 2.9 million estimate is for the number of people waiting for their initial application to be processed. Some recipients waiting for a decision reapplied directly to the states and were approved. Officials in many states will have to spend additional sums to weed out duplicate applications and eliminate the risk of double-counting.

Because not all states were able to report the number of people still waiting, it is difficult to discern broad trends. But it is clear that the largest pile of unprocessed applications in states that reported data were in eight relatively populous states. Those were: California (900,000 residents), Illinois (330,000), North Carolina (at least 298,840), Ohio (212,090), Virginia (183,643), Georgia (at least 159,313), Michigan (at least 123,381) and South Carolina (at least 113,429).

California and Illinois process their own applications. In others, technical problems prevented information sharing between healthcare.gov and state electronic systems.

In November, the Centers for Medicare and Medicaid Services allowed states to enroll people by using spreadsheets containing contact information and other personal data for people who tried to sign up through healthcare.gov. Six states still enroll people that way.

Many states have worked overtime to winnow down the paperwork. Ohio’s backlog from federal applications alone was 245,700 people in April. The state cut that down to 66,000 people by late May and hoped to reduce it to 25,000 or fewer by early June. Ohio also got 546,378 applications directly through state offices from Oct. 1 through April 30, 146,090 of which were still pending in May.

CMS officials estimate that almost 5 million more people enrolled in Medicaid from Oct. 1 through April 19 as a result of the health care law’s coverage expansion.