The deal, valued at more than $55 billion, is expected to be announced Tuesday, according to two people close to the companies who did not want to be identified discussing sensitive negotiations.
Bloomberg News first reported that Charter was poised to clinch its bid for Time Warner Cable, its long coveted prize.
The newly merged company also would include Bright House Networks. The three-company company combination would create a juggernaut, with about 17 million pay-TV subscribers in the U.S.
Charter also would become the largest pay-TV provider in Southern California, with 2 million customers in Los Angeles, Riverside, San Bernardino, San Diego, Ventura and Santa Barbara counties.
The proposed merger could break the logjam in the yearlong stalemate over distribution of the Los Angeles Dodgers' TV channel, SportsNet LA. For example, Charter could agree in the coming weeks to begin carrying the channel, which is owned by the Dodgers organization, for its current customers in Southern California.
Such a move would allow baseball fans in Burbank, La Cañada Flintridge, Long Beach and other areas served by Charter the opportunity to watch Dodger games on SportsNet LA -- an option those customers currently do not have. Time Warner Cable has been the only major distributor in Southern California to carry the network since it launched at the start of the 2014 baseball season.
Charter Chief Executive Tom Rutledge would run the new bulked up company, according to one person familiar with the terms of the proposed deal.
Charter, currently the nation's fourth-largest cable company, nearly two years ago made its first approach to Time Warner Cable executives. Early last year, Charter offered about $133 a share for Time Warner Cable.
But Time Warner Cable spurned Charter's advances and instead accepted an offer from Comcast Corp. The deal with Comcast, valued at about $45 billion, would have created the nation's largest Internet service and pay-TV provider.
However, federal regulators told Comcast in April that the deal would be blocked. The government was worried that Comcast would have too tight a grip on the nation's Internet connections. After that deal fell apart, Charter renewed its talks with Time Warner Cable's CEO, Robert Marcus.
Charter's proposed offer of about $195 a share represents a 14% premium over Time Warner Cable's closing price on Friday.
The Charter-Time Warner Cable-Bright House deal also would require the approval of federal and state regulators. Federal officials are close to approving another blockbuster combination, AT&T's proposed $49-billion acquisition of DirecTV.
That merger, which would create the nation's largest pay-TV company, is expected to be completed in late June.
It was unclear Monday how long the regulatory review for the proposed Charter-Time Warner Cable combination might take, though it is likely to be a matter of months.