Three Key Battleground States Within Polling Margin of Error

— -- Donald Trump has a slight lead in at least one key battleground state and is within the polling margin of error in three others.

The latest numbers from the CNN/ORC poll shows Trump taking a slight lead in Nevada, with 49 percent support from likely voters compared to Clinton's 43 percent.

That marks an increase in his support since early October, when Clinton had 46 percent support and Trump had 44 percent in the state.

In Arizona, Trump has 49 percent support and Clinton has 44 percent, though that is within the margin of error of polling. Clinton's support in Arizona has grown since the last poll, in which Trump was still leading by 7 points.

The results in Florida and Pennsylvania also came within the polling margin of error, with Clinton receiving 49 percent to Trump's 47 percent in Florida and Clinton receiving 48 percent to Trump's 44 percent in Pennsylvania.

These four states are crucial to the electoral map and the candidates have been spending serious time and money to win over undecided voters there in recent days.

Libertarian candidate Gary Johnson is down from his previous results in all four states, with his highest results coming in Arizona and Nevada, where he received five percentage points apiece. In a mid-August CNN/ORC poll, Johnson received 12 percent of the vote in Arizona.

ABC News' Ryan Struyk contributed to this report.