It certainly helps to locate a will of an ancestor, especially if it enables us to discover the full mention of names in that family. Unlike some other wills I've encountered—listing, for instance, "my wife" or "my five children" without so much as the mention of any names—the possible father of my mother-in-law's third great-grandmother, Mary Carroll Gordon, was careful to include the names of those to whom he bequeathed his possessions.
Before we explore anything about the names listed in Anthony Carroll's 1830 will, let's see what we can discover about the man, himself. At the point of his death, Anthony's will was presented to the court in Monongalia County in what was then the state of Virginia. The date was only mentioned as the "February term 1830," but that clearly indicates that the many online trees showing Anthony's date of death in 1832 would not apply to this Anthony Carroll of Monongalia County.
So what can we find about this Anthony Carroll? Since he died, at the latest, sometime before the end of February of 1830, he wouldn't have appeared in the 1830 census, which was taken beginning on June 1. However, because the population of Monongalia County, at that point, was relatively small, it was not a difficult process to page through the handwritten records to see whether there were any Carroll family members still living in the same county. After all, Anthony's widow was likely still living there, since he had stipulated that she remain at his property after his death.
The census records for Monongalia County, with heads of households listed in roughly alphabetical order—all the surnames beginning with "C" in the same place, for instance—we can see right away whether there were any Carrolls mentioned on the two pages which covered that category. Sure enough, we can find an entry for a man by the name of William Carroll, and another entry for someone named John Carroll.
One of the benefits of the 1830 census was that the age categories used in previous decennial enumerations had been expanded to be more specific, especially for the older adult ages. Thus, we can tell that William Carroll was a man of at least thirty years of age but under forty. We can also see that his household included a woman aged between thirty and forty years, as well, plus six children all under the age of fifteen. If this were a relative of Anthony's widow, it does not appear that she was included in this household.
Turning to the household of John Carroll, we find another head of household aged between thirty and forty, along with a woman of the same age category. Together, they were responsible for five girls under the age of fifteen. However, once again, there was no sign of an older woman who might fit the age category of Anthony's widow.
Turning back in time to the 1820 census, we now can pick up signs of Anthony's whereabouts in Monongalia County. With this earlier census, the enumeration was completed over a thirteen month period, beginning on August 7. The age categories were more general than those utilized for the 1830 census, masking any delineation of adults older than forty five.
There, under the first page containing surnames beginning with the letter "C" we find Anthony "Carrill" or "Cassill," as it is indexed at FamilySearch.org. Unfortunately, the headings for the census pages are cut off from the digitized version—or, perhaps, were never included as headers in the first place. Complicating the matter is the fact that the format provided for the 1820 census does not align well with what we can see from the handwritten form for Monongalia County. Nevertheless, we can tell that there were three tick marks for the Carroll household. Whatever that meant, at least it indicated that, by 1820, Anthony Carroll was resident in Monongalia County.
Moving back to the 1810 census, Anthony was still resident in Monongalia County. Once again, the enumeration period for this census began in August of that year, and listed only heads of households, plus delineations of age categories for all others residing in the same household. For this census, we can find Anthony listed as "Anth. Carroll." With no headings included at the top of the census page, we can only assume that the entries for his household indicate one male forty five and older, one female within the same age range, plus two girls under ten and one fifteen years of age or younger.
Before that point, I can't locate Anthony Carroll in Monongalia County. This is not surprising, though, for several of the other families which have intermarried with this line had arrived there from somewhere in Maryland—and eventually moved on to the southwestern corner of Pennsylvania, not far away from Monongalia County.
With that, it's time to consider what we can find about some of those related families, especially those who were mentioned in Anthony's will. Let's look first to see what we can find about Anthony's daughter, the one listed as "Pegey Guseman" in that 1830 document.