Q:

creating array of bad names to check and replace in c#

I'm looking to create a method that loops through an list and replaces with matched values with a new value. I have something working below but it really doesnt follow the DRY principal and looks ugly. 
How could I create a dictionary of value pairs that would hold my data of values to match and replace?
           var match = acreData.data;

            foreach(var i in match)
            {   
                if (i.county_name == "DE KALB")
                {
                    i.county_name = "DEKALB";
                }
                if (i.county_name == "DU PAGE")
                {
                    i.county_name = "DUPAGE";
                }
             }

A:

In your question, you can try to use linq and Replace to make it.
var match = acreData.data.ToList();
match.ForEach(x =>
    x.county_name = x.county_name.Replace(" ", "")
);

or you can try to create a mapper table to let your data mapper with your value. as @user2864740 say.
Dictionary<string, string> dict = new Dictionary<string, string>();
dict.Add("DE KALB", "DEKALB");
dict.Add("DU PAGE", "DUPAGE");

var match = acreData.data;
string val = string.Empty;
foreach (var i in match)
{
    if (dict.TryGetValue(i.county_name, out val))
        i.county_name = val;
}

