The venue was sold out of the first three days as both sides piled on first-innings runs, but Monday’s play took place in front a much reduced crowd.
With the result still uncertain and the possibility of an England series win should the hosts find a way to wrap up a positive result, the county announced shortly after tea that entry would be complimentary.
Fans must register for access at tickets.trentbridge.co.uk and are encouraged to make a voluntary donation to the Trent Bridge Community Trust.
The club said: “The decision to permit free entry has been taken by Nottinghamshire County Cricket Club after a frankly thrilling four days sent the contest into its final chapter with all three results still possible.
“We hope that this gesture will encourage first-time visitors to join long-standing supporters at Trent Bridge and we can’t wait to welcome you to our historic home.”