Indiana’s deadline for write-in candidates to file for write-in status is July 5. In the past it was in October, but sometime in the last few years, the legislature made it far earlier. Such an early deadline is irrational. One of the chief purposes of allowing write-ins is so that voters retain flexibility if unexpected events occur during the last few months of the election campaign.
The second earliest write-in filing deadline is in Florida, July 12. The print issue of Ballot Access News, July 1, 2016, has all these deadlines.