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This compilation is the fourth data release from the $R$-Process Alliance(RPA) search for $r$-process-enhanced stars, and the second release based on"snapshot" high-resolution ($R \sim 30,000$) spectra collected with the du Pont2.5m Telescope. In this data release, we propose a new delineation between the$r$-I and $r$-II stellar classes at $\mathrm{[Eu/Fe]} = +0.7$, instead of theempirically chosen $\mathrm{[Eu/Fe]} = +1.0$ level previously in use, based onstatistical tests of the complete set of RPA data released to date. We alsostatistically justify the minimum level of [Eu/Fe] for definition of the $r$-Istars, [Eu/Fe] $> +0.3$. Redefining the separation between $r$-I and $r$-IIstars will aid in analysis of the possible progenitors of these two classes ofstars and whether these signatures arise from separate astrophysical sources atall. Applying this redefinition to previous RPA data, the number of identified$r$-II and $r$-I stars changes to 51 and 121, respectively, from the initialset of data releases published thus far. In this data release, we identify 21new $r$-II, 111 new $r$-I (plus three re-identified), and 7 new (plus onere-identified) limited-$r$ stars out of a total of 232 target stars, resultingin a total sample of 72 new $r$-II stars, 232 new $r$-I stars, and 42 newlimited-$r$ stars identified by the RPA to date.

The $R$-Process Alliance: Fourth Data Release from the Search for $r$-Process-Enhanced Stars in the Galactic Halo