Areas managed by my Agency don’t always match up with other areas’ boundaries by conscious/cooperative design

US admin boundaries mostly originate from TIGER; if they haven’t got fixed due to the personal initiative of some mappers they may be extremely off.

Within my Agency, we use a Conformal Conic projection (NAD 1983) since it minimizes area/shape warping, and keeps distances comparable. But even when I reproject my data to Web Mercator, it doesn’t match up well to other’s boundaries even when that is expected.

Should I simply match my areas to what is currently in place?

No. Your data is authoritatively correct; if your transformation is accurate as well you shall not worsen this in any kind.

OSM has been bad at alignment from the start (inaccurate GPS, badly aligned Bing imagery, badly aligned imports). You are lucky to bring more “survey control lines” into OSM by your import.

Thank you for your contributions and your commitment to learn JOSM ;)

Please only tag landscaped parks as leisure=park. Since your WMAs already have boundary_type=protected_area you may add a protect_class to get them rendered.