Solid-state nanopore single-molecule sensing aims to replace the commercially available biological nanopores. Array sizes have remained limited due to the area and power consumption of the transimpedance amplifiers (TIAs), thus preventing throughput and cost scaling. This article presents a 256-channel readout array for solid-state nanopore single-molecule sensing in 65 nm CMOS. Each channel contains a novel discrete-time TIA architecture, which is based on an Integrate and Reset concept and exploits source-degeneration to improve the noise performance. Each TIA is combined with a new event-detection architecture that allows disabling channels and reusing ADC resources, resulting in a 32× reduction in data rate. These innovations result in a more than 8× smaller channel area compared to the state-of-the-art while reaching an integrated noise performance of 193 pA rms in a 1 MHz bandwidth, thus enabling a 10× channel count scaling.