Company founding and incorporation dates are usually two different dates. For example Microsoft was founded in 1975 but was incorporated in 1981.
Below are a few places you can find these dates for an individual company and to create a list of companies founded or incorporated in a specific date range.
For an individual company, on the company's profile page look under the company title.
To build a list of companies founded in a date range:
In the top menu bar select Screening > Company Screening.
In the Company Details box in the lower left, select Company Statistics. Scroll down and select Year Founded, add the desired range, and press Add Criteria.
Add other screening criteria such as geographic location or industry classification, etc. and press View Results.