What female artists have the most number one albums?

As of my knowledge cut-off in September 2021, the female artists with the most number one albums on the Billboard 200 chart in the United States are:

1. Madonna - 12 number one albums

2. Barbra Streisand - 11 number one albums

3. Taylor Swift - 10 number one albums

4. Janet Jackson - 7 number one albums

5. Mariah Carey - 7 number one albums

Please note that this information may have changed since then, and there may be other female artists who have achieved more number one albums after September 2021. To stay up-to-date on the latest chart data, you can check the Billboard website or other reputable music publications.