Background: Data regarding critical care for patients with severe Covid-19 are limited. We aimed to describe the clinical course and critical care implemented for this patient population at the provincial level in Sichuan, China. Methods: In this population-based multicenter cohort study, conducted from January 16 to March 15, 2020, all microbiologically confirmed Covid-19 patients who met the national severe or critical criteria were included and followed-up until discharge, death, or the end of the study. Results: Out of 539 confirmed Covid-19 patients, 81 severe cases (15.0%) were identified. The median (IQR) age was 50 (39-65) years, 37% were female, and 53.1% had chronic comorbidities. Among the five predefined criteria for severe illness, low PaO2:FiO2 ratio (<300 mmHg), low pulse oxygen saturation (≤93%), and dyspnea were the most commonly reported, accounting for 87.7%, 66.7% and 27.2% of the severe cases, respectively. The median period from the onset of symptoms to the first hospitalization was 3 (1-6) days. Seventy-seven patients (95.06%) were admitted to hospitals being able to provide critical care by day 1. By day 28, 53 (65.4%) were discharged, 3 (3.7%) were deceased, and 25 (30.9%) were still hospitalized. Conventional oxygen therapy, administered to 95.1% of the patients, was the most commonly used respiratory support and met 62.7% of the respiratory support needed, followed by high-flow nasal cannula (19.5%) and noninvasive mechanical ventilation (10%). Conclusions: Early identification, hospitalization, and provision of critical care to severe Covid-19 patients may improve prognosis. Sufficient conventional oxygen equipment should be prioritized and implemented without delay.