EXHIBIT 21 Subsidiaries of the Registrant State of Doing Business Name of Subsidiary Incorporation As - ------------------------------------------ ----------------- ------------------ Bay Area Teleport, Inc. Delaware -- Conticomm, Inc. Colorado -- CSW/ICG ChoiceCom, L.P. Delaware -- Fiber Optic Technologies of Oregon, Inc. Oregon -- Fiber Optic Technologies, Inc. Colorado -- Grupo IntelCom de Mexico S.A. de C.V. Mexico -- ICG Access Services - Southeast, Inc. (formerly known as PrivaCom, Inc.) Delaware -- ICG Enhanced Services, Inc. Colorado -- ICG Holdings, Inc. (formerly known as IntelCom Group (U.S.A.), Inc.) Colorado -- ICG Holdings-Canada, Inc. (formerly known as IntelCom Group Inc.) Federal Canadian -- ICG Investments, Inc. Colorado -- ICG Fiber Optic Technologies, Inc. (formerly known as ICG Network Services, Inc.) Colorado FOT DataCom ICG Ohio LINX, Inc. Ohio -- ICG Satellite Services, Inc. (formerly known as Commden Ltd. and as ICG Wireless Services, Inc.) Colorado -- ICG Southwest Holdings, Inc. Colorado -- ICG SWL, Inc. Colorado -- ICG SWP, Inc. Colorado -- ICG Telecom Canada, Inc. Federal Canadian -- ICG Telecom Group, Inc. (formerly known as ICG Access Services, Inc.) Colorado -- ICG Telecom of San Diego, L.P. California -- ICG Telecom Services, Inc. Colorado -- IntelCom Red, S.A. de C.V. Mexico -- Maritime Cellular Tele-Network, Inc. Delaware -- Maritime Telecommunications Network, Inc. Colorado -- Nova-Net Communications, Inc. Colorado -- PTI Harbor Bay, Inc. Washington -- Southwest TeleChoice Management, LLC Delaware -- TDIJV, Inc. Colorado -- Teleport Denver Ltd. Colorado -- TransAmerican Cable, Inc. Kentucky MidAmerican Cable UpSouth Corporation Georgia -- Zycom Corporation Alberta, Canada -- Zycom Corporation Texas -- Zycom Network Services, Inc. Texas --