What do we call the noun to which a pronoun refers?

For example, if I say

We shall go from here to there.

and we are in New York intending to go to Boston, what would we say New York and Boston are to here and there, respectively?

A simple answer is that the general terms suitable in most discourse domains are 'referent' or 'token'. Which to use is your choice, although 'token' may raise an eyebrow here and there, and 'referent' may curl a lip here there and everywhere. In some technical discourse domains and contexts, where a finer degree of linguistic granularity is important or necessary, more specialized terms might be preferable.

Before I supply more specialized terms, however, I should attempt to remedy a misconception suggested by your question title and body. And I should make explicit that the specialized terms I mention are subject to controversy and disagreement among specialists, just as hairs may be split about the functions and meanings of 'here' and 'there' themselves.

First, to clear up the misconception suggested by the conflict between your question title and the body of your question. The indexicals (so-called because they point like an index finger) here and there, also sometimes called demonstrative adverbs (etc., including "pointing words"), are not pronouns. 'Here' and 'there' may function as nouns or adverbs. In some obsolete instances and combining forms 'here' and 'there' may also be used as adjectives.

The example in your question does not allow an easy resolution of which specialized term among those suggested by the following extract from Fretheim et al. regarding 'here' would be most appropriate:

...there is a single lexical item here, but this word can be put to three major uses, (i) as a token-reflexive term, (ii) as an anaphoric term, and (iii) as a deictic term. The contextual assumptions that an addressee brings to bear in the referential interpretation of this indexical in English and its equivalent in other languages will determine whether a given token of it is deictic, token-reflexive or anaphoric, or, as we are going to argue, a combination of two of the three categories.

Page 241 (PDF page 3) of Fretheim, Thorstein, Nana Aba Appiah Amfo & Ildikó Vaskó. 2011. Token-reflexive, anaphoric and deictic functions of ‘here’. Nordic Journal of Linguistics 34(3), 239–294.

In the case of (i), when 'here' is used as a token-reflexive term (also called, e.g., an 'egocentric particular'), then 'here-token' might be the most appropriate technical term to use for the referent. In the case of (ii), when 'here' is used as an anaphoric term, then 'antecedent' might be the most appropriate term. In the case of (iii), of course, there is no linguistic referent of the indexical 'here', only a contextual referent.

Hence the difficulty of answering your question: the context you provide in the question is not sufficiently specified to allow a specific answer, only general answers. In case (iii), for example, the indexicals here and there may be referring to places being pointed at on a map.

The application of the foregoing to 'there' is left as an exercise for the reader.

An antecedent is the noun/noun phrase that a pronoun refers back to.

Pronoun-antecedent agreement is an important part of the English language.

Every woman must learn the fundamentals of etiquette if they wish to do well in society. (Incorrect, every woman = singular / they = plural)

Every woman must learn the fundamentals of etiquette if she wishes to do well in society. (Correct, every woman = singular / she = singular)

One must make sure that pronouns and antecedents match in number (singular or plural), person (1st, 2nd, or 3rd), and gender (male, female, unspecified).