There is a platted addition to a city that was chartered in 1909 and apparently that charter was surrendered to the State in 1911. This former "town" is located just outside the current city limits of Uvalde. The plat shows that the addition in question has named streets and dedicated alleys.
A group of nine landowners has petitioned the Commissioner's Court to abandon the streets and alleys within the Addition, with the abandoned property passing to the adjoining landowner. This group makes up all but one of the landowners. As far as I can tell there would be no issue of access to a public road for the current landowners. The petitioners are claiming that the "roads" have been fenced off for over forty years and there has never been any roads or alleys established other than by the plat that was recorded almost 100 years ago. I am aware of Trans. Code 251.057 and 251.058 regarding abandonment of roads.
My main concerns, at this point, are: (1) Does the fact that the property is within the ETJ of the City of Uvalde have any bearing on this and, (2) Can the court just abandon without doing more, i.e. notice, posting, etc?
I am sure that there is something else that I am missing which is why you are reading this. Any thoughts would be appreciated. Thanks.

Transp Code 251.052(c) has a posting requirement...I think it has to be posted for 20 days. We had it posted in the rural post office nearest the road, and also on a fencepost by the road. Our commissioners are reluctant to close any county roads, even if they are no longer maintained, because the commissioners get part of their road and bridge money from the state based on the mileage of county roads in each precinct.

Has the county maintained the roads in the past? (that is, that any one is CERTAIN of?) If not, that, coupled with the strong probability that the county never formally accepted responsibility for the roads may leave you in a position of no authority over them. Do they show on your 911 map as county, public or private?

In my opinion, if the roads were accepted by act of the Commissioners or by action (is maintenance), your best path is to close the roads with all due formality. Post notice of the proposition near the roads and in some other public place, and remind your commissioners that this requires a unanimous vote. If the roads are on your 911 map as county, be sure that this is changed ASAP.

With regards to the city, I would clue the City Commission in on what is happening. To keep things a little cleaner, they may want to pass a resolution in support or some such thing.

But remember - while all county roads are public, not all public roads are county responsibility. You may have no authority what ever over these.

Have fun!

You should also be aware of 263.002 of the Texas Local Government Code that speaks to the same issue as the Transportation Code sections you cite. I also share Lisa's concern that the County may not even own the roads.