By the late 20th century, those lands allotted to individual Native Americans had been divided zillions of times among heirs to the land. For example, in a court ruling about the problem, here's the fate of one of the original tracts:

Tract 1305 is 40 acres, and produces $1,080 in income annually. It is valued at $8,000. It has 439 owners, one-third of whom receive less than $.05 in annual rent and two-thirds of whom receive less than $1. The largest interest holder receives $82.85 annually. The common denominator used to compute fractional interests in the property is 3,394,923,840,000. The smallest heir receives $.01 every 177 years. If the tract were sold (assuming the 439 owners could agree) for its estimated $8,000 value, he would be entitled to $.000418. The administrative costs of handling this tract are estimated by the Bureau of Indian Affairs at $17,560 annually(source).

Talk about a broken system.

In 1983, in an attempt to solve the problem, the government passed the Indian Land Consolidation Act. Under this Act, those tiny fractionated allotments would not be passed down to heirs; they'd revert to tribal ownership if the value was under a certain amount; the tribes were given some authority about what would happen to this land. The Act was amended a bunch of times to tighten up the definition of "Indian" and to set some conditions on the reverted lands. In 2000, the government specifically stated the goals of the program:

It is the policy of the United States— (1) to prevent the further fractionation of trust allotments made to Indians; (2) to consolidate fractional interests and ownership of those interests into usable parcels; (3) to consolidate fractional interests in a manner that enhances tribal sovereignty; (4) to promote tribal self-sufficiency and self-determination; and (5) to reverse the effects of the allotment policy on Indian tribes (source).

The final result of all the amendments was the 2012 creation of the Indian Land Consolidation Program, which authorized the U.S. government to buy back these fractionated parcels and give them back to the tribes who had jurisdiction over that land only if the individuals who owned them would be willing to sell them for fair-market value (source).

The program was designed to last for ten years. As of 2017, the program had spent $1.3 billion, but it isn't clear if it made a dent on the problem. In May 2017, the acting Secretary of the Interior said,

"I view the Buy-Back Program as a once in a lifetime opportunity to meaningfully address fractional interests that plague tribal communities and their efforts towards sovereignty and self-determination. [I]n my mind we are almost back where we started eight years later, just treading water" (source).

Stay tuned, Shmoopers. The last chapter in this history has yet to be written.