The END CELLS Act amends federal communications law to create stricter rules and penalties around bringing cell phones and other wireless devices into prisons, jails, and other detention facilities. The bill makes it illegal for anyone to provide such devices to inmates or knowingly smuggle them into facilities, and it makes it illegal for detainees to possess or obtain wireless devices in violation of facility rules. Violators face civil penalties up to $50,000 per violation or $1,000,000 total for a single act, as well as criminal fines of up to $50,000 for willful violations. The law applies to all detention facilities in the United States and takes effect immediately upon passage. The legislation does not specify new funding but does streamline the enforcement process by waiving certain procedural requirements that normally apply to similar communications violations.