Copied from USCIS:
We are planning to open a new facility in Elgin, Illinois, next year to expand our lockbox capability.
To prepare for this shift, on Oct. 15 we adjusted the filing locations for some applications. Now, certain adjustment of status applicants submit their applications to the Phoenix Lockbox instead of the Chicago or Dallas Lockbox. Additionally, we have streamlined filing locations for certain employment-based forms to a single lockbox location. You can find the latest filing instructions on our Form I-130, I-131, I-360, I-485, I-601, I-765, I-824, and I-864 pages.
In the coming year, we are planning a few more filing location changes. We will continue to balance incoming volumes by directing some family-based adjustment of status applications to Dallas. Early next year, we will add Elgin as a filing location. Next summer, we will be moving the lockbox facility in Arizona from Phoenix to Tempe.
Applicants who submit their application to an incorrect location may experience delays in processing their case. For the most current information on where to file, please see the “Where to File” section on the webpage for your form. You can also subscribe to the “Forms Updates” GovDelivery distribution list to receive an email each time we update a filing location.